Pushpad: subscribe prompt only showed up the first time a user clicks on enable button on chrome - google-chrome

Hello,
I already checked the answers from the question PushPad: Subscribe is removed after site refresh, but it did not help me.
I created a subscribe/unsubscribe button, following the doc, and the prompt is showing up on Firefox each time i click on the subscribe button so i guess my flow is correct but i don't understand why it's not working on Chrome => the prompt is only showing the first time i launch Chrome.
Here is what i do
pushpad('init', #projectID);
var pushId = $("#main").data("pushid");
var pushSig = $("#main").data("pushsig");
var updateButton = function (isSubscribed) {
var btn = $('#activate-push-notif');
if (isSubscribed) {
btn.html('Unsubscribe');
btn.addClass('subscribed');
} else {
btn.html('Subscribe');
btn.removeClass('subscribed');
}
};
// check whether the user is subscribed to the push notifications and
// initialize the button status (e.g. display Subscribe or Unsubscribe)
pushpad('status', updateButton);
// when the user clicks the button...
$('#activate-push-notif').on('click', function (e) {
e.preventDefault();
// if he wants to unsubscribe
if ($(this).hasClass('subscribed')) {
pushpad('unsubscribe', function () {
updateButton(false);
}, {
uid: pushId,
});
// if he wants to subscribe
} else {
// try to subscribe the user to push notifications
pushpad('subscribe', function (isSubscribed) {
if (isSubscribed) {
updateButton(true);
} else {
updateButton(false);
alert('You have blocked notifications from your browser preferences.');
}
}, {
uid: pushId,
uidSignature: pushSig
});
}
});
Thanks for your help to figure it out.

Make sure that you wrap all your code inside $(function () { ... }, so that your code is run when the page is fully loaded, otherwise your click handler may not work properly.
Probably the point is that when you see the Firefox prompt you click "Not now" (instead of "Never allow" which is hidden under the ▼ menu). That is why you can see the prompt multiple times. In other browsers, like Chrome, the default option is "Block" (which is a permanent block, like "Never allow").
When the user blocks the notifications you cannot display the browser prompt again, due to browser restrictions... however there are some alternative solutions. For example you can display a custom prompt as many times as you want, and then display the browser prompt only if the user says yes to your custom prompt. See this example. Otherwise you can display a prompt only to users who have blocked the notifications, asking to unblock the notifications. See this example. Another option is to display a button in the page to allow the users to subscribe to notifications when they decide to do that.

Related

Should the window.statechange be triggered when I navigate back from an external link?

I'm using History.js (the jquery.history.js v1.8b2). Chrome version 30.0.1599.101 m.
I can't figure out how to make History.js work the way I'd expect.
I have a page that has two links. The first simulates an ajax operation. It just changes the text in an <h2> in the page from "start" to "2". The second link just points to google.com.
Here's what I do:
Clear cache in chrome
Load the page
Click the first link (I call pushState, statechange occurs and there I update my text to "2")
Click the google.com link (goes to google)
Click the browser Back button.
Upon back button click, I expect that the statechange handler should be called and I would then get my state object so I could restore the text to "2".
But the handler is not called. So my page is left with text "start" (the cached page in the browser). Interestingly, the url is set to the "2" version that I pushed in my pushState call.
Am I missing something? Here is my code:
<h2 id="state">start</h2>
<a id="2" class="button" href="#">Goto State 2</a>
Goto google
<script type="text/javascript">
$(function() {
History.Adapter.bind(window, "statechange", function() {
console.log("statechange called");
var state = History.getState();
if (state.data.mystate) {
// Restore the old state
$("#state").text(state.data.mystate);
} else {
// Start state
$("#state").text("start");
}
});
$(".button").click(function(e) {
// push the state we're transitioning to
var newState = $(this).attr("id");
History.pushState(
{ mystate: newState },
"at state " + newState,
"http://localhost:50494/PushState?state=" + newState);
// statechange will be called now, and we'll update the page from our newState
e.preventDefault();
});
});
</script>
I think the answer is no, the statechange isn't supposed to be called when navigating back from outside the page.
I noticed that the demo at http://browserstate.github.com/history.js/demo/ was working as I'd expect, so I did a view source to see how it was working. From what I can tell, here is how you are supposed to use History.js.
When your page loads, you look at History.getState().data. If you recognize one of your states there, then it means you are navigating back into your page from a different page, like from an external link you went to. (Note: the browser may have just loaded your page from cache or it could have been reloaded from the server. Shouldn't matter because you're going to update the page/ui with the state you just found). So, update your page to that state. If you didn't recognize the state, then it's a first time load as far as your page is concerned. Init appropriately.
The statechange event will get called upon the browser back/forward button between "ajax" states within your page (states you've pushed while in this one page). It will also get called when you call pushState(). Huh, isn't that confusing? Yes, so when you want to transition to a new state within your page, follow this pattern:
Prepare your state object (could involve an ajax call),
Call pushState(yourObject,...)
Don't update your page/ui yet.
You actually update your page/ui from the statechanged handler that's gonna get called in a moment.
I mistakenly thought you were supposed to do all the work of updating the page, then push the state afterward. This will just make things hard, since statechanged is gonna get called too.
Also, it appears that in general, you should push states for ajax-like transitions within the one page you're on. Don't push states for links you follow outside the page (unless you really understand all this and are trying to do something fancy).
I've updated the sample code here to show what's working for me now:
<h2 id="state">start</h2>
<a id="2" class="button" href="#">Goto State 2</a>
Goto google
<script type="text/javascript">
$(function () {
// page loading, check for available state I recognize
var availableState = History.getState();
if (!availableState.data.mystate) {
// loading for the first time
$("#state").text("start");
} else {
// load from the available state
loadState(availableState);
}
History.Adapter.bind(window, "statechange", function () {
var state = History.getState();
loadState(state);
});
function loadState(state) {
if (state.data.mystate) {
// update the page to this state
$("#state").text(state.data.mystate);
} else {
// update the page to the initial state
$("#state").text("start");
}
}
$(".button").click(function (e) {
// The user clicked a button, so we want to transition to a new state
// in this page. Push the state we're transitioning to (which we've hidden
// in the id attribute in this example).
var newState = $(this).attr("id");
History.pushState(
{ mystate: newState },
"at state " + newState, // title
"?state=" + newState); // url
// statechange will be called now, and we'll update the page from our newState
e.preventDefault();
});
});
</script>

Selectively remove Chrome browsing history

Is it possible to selectively remove items from Google Chrome browsing history? I have a website from my history that wants to be the default everytime I start a search with a specific letter, but I often reference my history to re-find things.
So I would like to remove all history from, say, www.pythonismyfavoritest.com without removing everything; is that possible?
Try searching www.pythonismyfavoritest.com in the search bar in chrome://history/ and then remove each item by clicking the check box in the left and then hitting the "remove selected items" button.
The chrome history api works with url such chrome://history/#q=hello&p=0
Here's something I wrote in JavaScript. It works through the Console Debugger. I tried using it in a bookmark but I get no response from the page.
** // UPDATE (07.28.15)
I added a shorter approach provided by #Denis Gorbachev to the checkbox targeting, which helped shorten some of this code. I also added "auto-stop" functionality, meaning the loop will stop once it has finally cleared the list.
** // UPDATE (08.20.14)I made a few changes to the code, to make it more user friendly. Other users may not be code-savvy, and others may simply prefer convenience. Therefore, I whipped up a couple buttons (start/stop) to control the usage; as well as address some "ASSERTION FAILED" exceptions/errors that were being thrown when attempted to run the script loop.. Enjoy!!
In your address bar, type in the following address to to the meat of the history page.. It's normally loaded in an iframe, with the left-side menu loaded in another frame.. // **
chrome://history-frame/
Next, load your Console Debugger/Viewer by pressing Ctrl+Shift+J(For Mac users, ⌘+⌥+J)
You can also press F12 and select the "Console" tab.
In the Console Debugger/Viewer, copy & paste the following code:
function removeItems() {
removeButton = document.getElementById('remove-selected');
overlayWindow = document.getElementById('overlay');
//revision (07.28.15): Replaced the For Loop targeting the checkboxes, thanks to Denis Gorbachev via comments (02.19.15)
Array.prototype.forEach.call(document.querySelectorAll("input[type=checkbox]"), function(node) {node.checked = "checked"})
setTimeout(function () {
if (removeButton.getAttribute("disabled") !== null) {
removeButton.removeAttribute("disabled")
}
/* revision (08.20.14): no longer binding to that condition, button should no longer be disabled, so click! */
if ((overlayWindow.hasAttribute("hidden")) && (overlayWindow.getAttribute("hidden") !== false)) {
removeButton.click();
}
/* revision (08.20.14): new Interval, to check against the overlay DIV containing the confirmation "Remove" button */
/* Attempting to click the button while the DIV's "hidden" attribute is in effect will cause FAILED ASSERTION */
stopButton = setInterval(function () {
if (overlayWindow.hasAttribute("hidden")) {
if (overlayWindow.getAttribute("hidden") == "false") {
hidden = false
} else {
hidden = true
}
} else {
hidden = false
}
if (!hidden) {
document.getElementById("alertOverlayOk").click();
clearInterval(stopButton)
}
}, 250)
}, 250)
}
//revision (08.20.14): Lets build our buttons to control this so we no longer need the console
//stop button (08.20.14)
var stopButton = document.createElement('button');
stopButton.setAttribute('id', "stopButton");
stopButton.innerHTML = "Stop";
stopButton.style.background = "#800";
stopButton.style.color = "#fff";
stopButton.style.display = "none";
stopButton.onclick = function () {
clearInterval(window.clearAllFiltered);
document.getElementById("stopButton").style.display = "none";
document.getElementById("startButton").style.display = ""
};
//start button (08.20.14)
var startButton = document.createElement('button');
startButton.setAttribute('id', "startButton");
startButton.innerHTML = "Start";
startButton.style.background = "#090";
startButton.style.color = "#fff";
startButton.onclick = function () {
window.clearAllFiltered = setInterval(function () {
/* revision (07.28.15): Stop the Loop automatically if there are no more items to remove */
if(document.getElementById("results-header").innerText=="No search results found."){
document.getElementById("stopButton").click();
}
if (document.getElementById("loading-spinner").getAttribute("hidden") !== null) {
removeItems()
}
}, 250); //adjust Time Here (1500 [millisec] = 1.5sec)
document.getElementById("stopButton").style.display = "";
document.getElementById("startButton").style.display = "none"
};
/* revision (08.20.14): Now we add our buttons, and we're ready to go! */
editingControls = document.getElementById('editing-controls');
editingControls.appendChild(stopButton);
editingControls.appendChild(startButton);
This removeItems function will select loop through all form inputs and check all checkboxes, enable the "Remove Selected Items" button and click it. After a half-second, it'll check if the "Are You Sure" prompt is displayed and, if so, click the "Yes/Remove" button automatically for you so that it will load a new list of items to do this process all over again..
The item is looped using the variable "clearAllFiltered", which is a setInterval loop, which is checking for the status of the "Loading" screen..
To start erasing your filtered history items, you can now click the green Start button.
** // UPDATE (07.28.2015) It will now stop on ITS OWN.
To stop the loop manually, you can now click the red Stop button. Simple as that!
1) Go to your history settings ( chrome://history/ )
2) In the top right hand corner will be a search bar with a 'Search History" button
3) Type in the sitename you want to remove from history, then click the button
4) Click the box on the first one, then scroll to the bottom of the page
5) Press and hold the Shift key, then click the last box (This will check all on that page)
6) Scroll back up and select the 'Remove Selected Items" Button
7) Repeat steps 4-6 until all your Youtube History is gone.
Hopefully Chrome will update this clear history feature, but for now this seems to be the fastest option
Easy way is Shift+Delete.
For example when you type "you", "youtube.com" will be shown as selected in suggestions. Just click Shift+Delete. Then retype "you" and you will see no "youtube.com" in that list anymore.
If you are talking about getting rid of the suggested search/auto-completion... then removing specific items from your chrome://history won't do it (in my experience). I want to fill in more detail to the answer #LacOniC gave.
In the screenshot you can see I typed "ba" and Chrome is suggesting completion based on my browsing history (the items in green).
In my experience, removing specific items from your history will not remove them from showing up in this address bar auto-completion.
To quickly remove these auto complete items:
Start typing a few letters that generate the offending suggestion.
Use your keyboard's arrow keys to select the suggestion you don't like (selected item is highlighted blue in screenshot).
Press shift+delete on windows or shift+fn+delete on mac to remove the selected item.

How to disable Webkit Notifications?

Is there a way I can give a user the option of disabling webkitNotifications? If I call requestPermission() a second time, it does not prompt the user.
I just ask for the permissions once, then I let the user configure whether he wants to receive notifications from a configuration panel.
You can store this option in a database on the server or client-side with localStorage.
Display notification
if (notificationsEnabled) {
var notification = new window.Notification("Hello");
}
Restore setting on load
$(function () {
notificationsEnabled = JSON.parse(localStorage.getItem('notificationsEnabled') || false);
$('#notificationsEnabled').prop('checked', notificationsEnabled);
if (!window.Notification) {
$('#notificationsEnabled').prop('disabled', true);
}
});
Settings
<label>
<input id="notificationsEnabled" name="notificationsEnabled" type="checkbox">
Enable notifications
</label>
Handle onchange events on the checkbox
$('#notificationsEnabled').on('change', function() {
notificationsEnabled = !notificationsEnabled;
localStorage.setItem('notificationsEnabled', notificationsEnabled);
if (notificationsEnabled && window.Notification.permission === 'default') {
window.Notification.requestPermission();
}
});
You could try presetting users preferences for notifications in code:
http://developer.apple.com/library/safari/#documentation/AppleApplications/Conceptual/SafariJSProgTopics/Articles/SendingNotifications.html
If you're in Chrome try this:
Bring up the menu (it's hidden to the right of the address bar)
Click "Settings"
Click "Show advanced settings..."
Under "Privacy" click "Content Settings"
Under "Notifications" click "Manage exceptions"
You can reset the notifications there.

How to listen to history events like "go back", "go next" in Chrome extension?

For now, I've only found a way to listen to "reload" event using:
chrome.webNavigation.onCommitted.addListener(function(details) {
if (details.frameId == 0) {
if (details.transitionType == "reload") {
// do something
}
}
});
What about "go back" and "go next" events? I'm looking for a Firefox's nsISHistoryListener alternative in Chrome.
Edit: Submitted a feature request to Chromium.
You could use the window.beforeunload event to capture when a user intends to navigate to another page (which would be triggered when using the back and forward buttons).
window.onbeforeunload = function () {
// do something
};
There is no way to get the target destination when using onbeforeunload.
More info here: Is there a cross-browser onload event when clicking the back button?

How to detect when cancel is clicked on file input?

How can I detect when the user cancels a file input using an html file input?
onChange lets me detect when they choose a file, but I would also like to know when they cancel (close the file choose dialog without selecting anything).
While not a direct solution, and also bad in that it only (as far as I've tested) works with onfocus (requiring a pretty limiting event blocking) you can achieve it with the following:
document.body.onfocus = function(){ /*rock it*/ }
What's nice about this, is that you can attach/detach it in time with the file event, and it also seems to work fine with hidden inputs (a definite perk if you're using a visual workaround for the crappy default input type='file'). After that, you just need to figure out if the input value changed.
An example:
var godzilla = document.getElementById('godzilla')
godzilla.onclick = charge
function charge()
{
document.body.onfocus = roar
console.log('chargin')
}
function roar()
{
if(godzilla.value.length) alert('ROAR! FILES!')
else alert('*empty wheeze*')
document.body.onfocus = null
console.log('depleted')
}
See it in action: http://jsfiddle.net/Shiboe/yuK3r/6/
Sadly, it only seems to work on webkit browsers. Maybe someone else can figure out the firefox/IE solution
So I'll throw my hat into this question since I came up with a novel solution. I have a Progressive Web App which allows users to capture photos and videos and upload them. We use WebRTC when possible, but fall back to HTML5 file pickers for devices with less support *cough Safari cough*. If you're working specifically on an Android/iOS mobile web application which uses the native camera to capture photos/videos directly, then this is the best solution I have come across.
The crux of this problem is that when the page loads, the file is null, but then when the user opens the dialog and presses "Cancel", the file is still null, hence it did not "change", so no "change" event is triggered. For desktops, this isn't too bad because most desktop UI's aren't dependent on knowing when a cancel is invoked, but mobile UI's which bring up the camera to capture a photo/video are very dependent on knowing when a cancel is pressed.
I originally used the document.body.onfocus event to detect when the user returned from the file picker, and this worked for most devices, but iOS 11.3 broke it as that event is not triggered.
Concept
My solution to this is *shudder* to measure CPU timing to determine if the page is currently in the foreground or the background. On mobile devices, processing time is given to the app currently in the foreground. When a camera is visible it will steal CPU time and deprioritize the browser. All we need to do is measure how much processing time our page is given, when camera launches our available time will drop drastically. When the camera is dismissed (either cancelled or otherwise), our available time spike back up.
Implementation
We can measure CPU timing by using setTimeout() to invoke a callback in X milliseconds, and then measure how long it took to actually invoke it. The browser will never invoke it exactly after X milliseconds, but if it is reasonable close then we must be in the foreground. If the browser is very far away (over 10x slower than requested) then we must be in the background. A basic implementation of this is like so:
function waitForCameraDismiss() {
const REQUESTED_DELAY_MS = 25;
const ALLOWED_MARGIN_OF_ERROR_MS = 25;
const MAX_REASONABLE_DELAY_MS =
REQUESTED_DELAY_MS + ALLOWED_MARGIN_OF_ERROR_MS;
const MAX_TRIALS_TO_RECORD = 10;
const triggerDelays = [];
let lastTriggerTime = Date.now();
return new Promise((resolve) => {
const evtTimer = () => {
// Add the time since the last run
const now = Date.now();
triggerDelays.push(now - lastTriggerTime);
lastTriggerTime = now;
// Wait until we have enough trials before interpreting them.
if (triggerDelays.length < MAX_TRIALS_TO_RECORD) {
window.setTimeout(evtTimer, REQUESTED_DELAY_MS);
return;
}
// Only maintain the last few event delays as trials so as not
// to penalize a long time in the camera and to avoid exploding
// memory.
if (triggerDelays.length > MAX_TRIALS_TO_RECORD) {
triggerDelays.shift();
}
// Compute the average of all trials. If it is outside the
// acceptable margin of error, then the user must have the
// camera open. If it is within the margin of error, then the
// user must have dismissed the camera and returned to the page.
const averageDelay =
triggerDelays.reduce((l, r) => l + r) / triggerDelays.length
if (averageDelay < MAX_REASONABLE_DELAY_MS) {
// Beyond any reasonable doubt, the user has returned from the
// camera
resolve();
} else {
// Probably not returned from camera, run another trial.
window.setTimeout(evtTimer, REQUESTED_DELAY_MS);
}
};
window.setTimeout(evtTimer, REQUESTED_DELAY_MS);
});
}
I tested this on recent version of iOS and Android, bringing up the native camera by setting the attributes on the <input /> element.
<input type="file" accept="image/*" capture="camera" />
<input type="file" accept="video/*" capture="camcorder" />
This works out actually a lot better than I expected. It runs 10 trials by requesting a timer to be invoked in 25 milliseconds. It then measures how long it actually took to invoke, and if the average of 10 trials is less than 50 milliseconds, we assume that we must be in the foreground and the camera is gone. If it is greater than 50 milliseconds, then we must still be in the background and should continue to wait.
Some additional details
I used setTimeout() rather than setInterval() because the latter can queue multiple invocations which execute immediately after each other. This could drastically increase the noise in our data, so I stuck with setTimeout() even though it is a little more complicated to do so.
These particular numbers worked well for me, though I have see at least once instance where the camera dismiss was detected prematurely. I believe this is because the camera may be slow to open, and the device may run 10 trials before it actually becomes backgrounded. Adding more trials or waiting some 25-50 milliseconds before starting this function may be a workaround for that.
Desktop
Unfortuantely, this doesn't really work for desktop browsers. In theory the same trick is possible as they do prioritize the current page over backgrounded pages. However many desktops have enough resources to keep the page running at full speed even when backgrounded, so this strategy doesn't really work in practice.
Alternative solutions
One alternative solution not many people mention that I did explore was mocking a FileList. We start with null in the <input /> and then if the user opens the camera and cancels they come back to null, which is not a change and no event will trigger. One solution would be to assign a dummy file to the <input /> at page start, therefore setting to null would be a change which would trigger the appropriate event.
Unfortunately, there's no way official way to create a FileList, and the <input /> element requires a FileList in particular and will not accept any other value besides null. Naturally, FileList objects cannot be directly constructed, do to some old security issue which isn't even relevant anymore apparently. The only way to get ahold of one outside of an <input /> element is to utilize a hack which copy-pastes data to fake a clipboard event which can contain a FileList object (you're basically faking a drag-and-drop-a-file-on-your-website event). This is possible in Firefox, but not for iOS Safari, so it was not viable for my particular use case.
Browsers, please...
Needless to say this is patently ridiculous. The fact that web pages are given zero notification that a critical UI element has changed is simply laughable. This is really a bug in the spec, as it was never intended for a full-screen media capture UI, and not triggering the "change" event is technically to spec.
However, can browser vendors please recognize the reality of this? This could be solved with either a new "done" event which is triggered even when no change occurs, or you could just trigger "change" anyways. Yeah, that would be against spec, but it is trivial for me to dedup a change event on the JavaScript side, yet fundamentally impossible to invent my own "done" event. Even my solution is really just heuristics, if offer no guarantees on the state of the browser.
As it stands, this API is fundamentally unusable for mobile devices, and I think a relatively simple browser change could make this infinitely easier for web developers *steps off soap box*.
You can't.
The result of the file dialog is not exposed to the browser.
When you select a file and click open/cancel, the input element should lose focus aka blur. Assuming the initial value of the input is empty, any non empty value in your blur handler would indicate an OK, and an empty value would mean a Cancel.
UPDATE: The blur is not triggered when the input is hidden. So can't use this trick with IFRAME-based uploads, unless you want to temporarily display the input.
Most of these solutions don't work for me.
The problem is that you never know which event will be triggered fist,
is it click or is it change? You can't assume any order, because it probably depends on the browser's implementation.
At least in Opera and Chrome (late 2015) click is triggered just before 'filling' input with files, so you will never know the length of files.length != 0 until you delay click to be triggered after change.
Here is code:
var inputfile = $("#yourid");
inputfile.on("change click", function(ev){
if (ev.originalEvent != null){
console.log("OK clicked");
}
document.body.onfocus = function(){
document.body.onfocus = null;
setTimeout(function(){
if (inputfile.val().length === 0) console.log("Cancel clicked");
}, 1000);
};
});
/* Tested on Google Chrome */
$("input[type=file]").bind("change", function() {
var selected_file_name = $(this).val();
if ( selected_file_name.length > 0 ) {
/* Some file selected */
}
else {
/* No file selected or cancel/close
dialog button clicked */
/* If user has select a file before,
when they submit, it will treated as
no file selected */
}
});
The new File System Access API will make our life easy again :)
try {
const [fileHandle] = await window.showOpenFilePicker();
const file = await fileHandle.getFile();
// ...
}
catch (e) {
console.log('Cancelled, no file selected');
}
Browser support is very limited (Jan, 2021). The example code works well in Chrome Desktop 86.
Just listen to the click event as well.
Following from Shiboe's example, here's a jQuery example:
var godzilla = $('#godzilla');
var godzillaBtn = $('#godzilla-btn');
godzillaBtn.on('click', function(){
godzilla.trigger('click');
});
godzilla.on('change click', function(){
if (godzilla.val() != '') {
$('#state').html('You have chosen a Mech!');
} else {
$('#state').html('Choose your Mech!');
}
});
You can see it in action here: http://jsfiddle.net/T3Vwz
You can catch the cancel if you choose the same file as previously and you click cancel: in this case.
You can do it like this:
<input type="file" id="myinputfile"/>
<script>
document.getElementById('myinputfile').addEventListener('change', myMethod, false);
function myMethod(evt) {
var files = evt.target.files;
f= files[0];
if (f==undefined) {
// the user has clicked on cancel
}
else if (f.name.match(".*\.jpg")|| f.name.match(".*\.png")) {
//.... the user has choosen an image file
var reader = new FileReader();
reader.onload = function(evt) {
try {
myimage.src=evt.target.result;
...
} catch (err) {
...
}
};
}
reader.readAsDataURL(f);
</script>
The easiest way is to check if there are any files in temporary memory. If you want to get the change event every time user clicks the file input you can trigger it.
var yourFileInput = $("#yourFileInput");
yourFileInput.on('mouseup', function() {
$(this).trigger("change");
}).on('change', function() {
if (this.files.length) {
//User chose a picture
} else {
//User clicked cancel
}
});
In my case i had to hide submit button while users were selecting images.
This is what i come up:
$(document).on('click', '#image-field', function(e) {
$('.submit-button').prop('disabled', true)
})
$(document).on('focus', '#image-field'), function(e) {
$('.submit-button').prop('disabled', false)
})
#image-field is my file selector. When somenone clicks on it, i disable the form submit button. The point is, when the file dialog closed - doesn't matter they select a file or cancel - #image-field got the focus back, so i listen on that event.
UPDATE
I found that, this does not work in safari and poltergeist/phantomjs. Take this info into account if you would like to implement it.
Shiboe's solution would be a good one if it worked on mobile webkit, but it doesn't. What I can come up with is to add a mousemove event listener to some dom object at the time that the file input window is opened, like so:
$('.upload-progress').mousemove(function() {
checkForFiles(this);
});
checkForFiles = function(me) {
var filefield = $('#myfileinput');
var files = filefield.get(0).files;
if (files == undefined || files[0] == undefined) $(me).remove(); // user cancelled the upload
};
The mousemove event is blocked from the page while the file dialog is open, and when its closed one checks to see if there are any files in the file input. In my case I want an activity indicator blocking things till the file is uploaded, so I only want to remove my indicator on cancel.
However this doesn't solve for mobile, since there is no mouse to move. My solution there is less than perfect, but I think its good enough.
$('.upload-progress').bind('touchstart', function() {
checkForFiles(this);
});
Now we're listening for a touch on the screen to do the same files check. I'm pretty confident that the user's finger will be put on the screen pretty quickly after cancel and dismiss this activity indicator.
One could also just add the activity indicator on the file input change event, but on mobile there is often a few seconds lag between selecting the image and the change event firing, so its just much better UX for the activity indicator to be displayed at the start of the process.
I found this atribute, its most simple yet.
if ($('#selectedFile')[0].files.length > 1)
{
// Clicked on 'open' with file
} else {
// Clicked on 'cancel'
}
Here, selectedFile is an input type=file.
I know this is a very old question but just in case it helps someone, I found when using the onmousemove event to detect the cancel, that it was necessary to test for two or more such events in a short space of time.
This was because single onmousemove events are generated by the browser (Chrome 65) each time the cursor is moved out of the select file dialog window and each time it is moved out of the main window and back in.
A simple counter of mouse movement events coupled with a short duration timeout to reset the counter back to zero worked a treat.
Combining Shiboe's and alx's solutions, i've got the most reliable code:
var selector = $('<input/>')
.attr({ /* just for example, use your own attributes */
"id": "FilesSelector",
"name": "File",
"type": "file",
"contentEditable": "false" /* if you "click" on input via label, this prevents IE7-8 from just setting caret into file input's text filed*/
})
.on("click.filesSelector", function () {
/* do some magic here, e.g. invoke callback for selection begin */
var cancelled = false; /* need this because .one calls handler once for each event type */
setTimeout(function () {
$(document).one("mousemove.filesSelector focusin.filesSelector", function () {
/* namespace is optional */
if (selector.val().length === 0 && !cancelled) {
cancelled = true; /* prevent double cancel */
/* that's the point of cancel, */
}
});
}, 1); /* 1 is enough as we just need to delay until first available tick */
})
.on("change.filesSelector", function () {
/* do some magic here, e.g. invoke callback for successful selection */
})
.appendTo(yourHolder).end(); /* just for example */
Generally, mousemove event does the trick, but in case user made a click and than:
cancelled file open dialog by escape key (without moving a mouse), made another accurate click to open file dialog again...
switched focus to any other application, than came back to browser's file open dialog and closed it, than opened again via enter or space key...
... we won't get mousemove event hence no cancel callback. Moreover, if user cancels second dialog and makes a mouse move, we'll get 2 cancel callbacks.
Fortunately, special jQuery focusIn event bubbles up to the document in both cases, helping us to avoid such situations. The only limitation is if one blocks focusIn event either.
I see that my response would be quite outdated, but never the less.
I faced with the same problem. So here's my solution.
The most useful code snipped was KGA's one. But it isn't totally working and is a bit complicated. But I simplified it.
Also, the main trouble maker was that fact, that 'change' event doesn't come instantly after focus, so we have to wait for some time.
"#appendfile" - which user clicks on to append a new file.
Hrefs get focus events.
$("#appendfile").one("focusin", function () {
// no matter - user uploaded file or canceled,
// appendfile gets focus
// change doesn't come instantly after focus, so we have to wait for some time
// wrapper represents an element where a new file input is placed into
setTimeout(function(){
if (wrapper.find("input.fileinput").val() != "") {
// user has uploaded some file
// add your logic for new file here
}
else {
// user canceled file upload
// you have to remove a fileinput element from DOM
}
}, 900);
});
You can detect this only in limited circumstances. Specifically, in chrome if a file was selected earlier and then the file dialog is clicked and cancel clicked, Chrome clears the file and fires the onChange event.
https://code.google.com/p/chromium/issues/detail?id=2508
In this scenario, you can detect this by handling the onChange event and checking the files property.
This is hacky at best, but here is a working example of my solution to detect whether or not a user has uploaded a file, and only allowing them to proceed if they have uploaded a file.
Basically hide the Continue, Save, Proceed or whatever your button is. Then in the JavaScript you grab the file name. If the file name does not have a value, then do not show the Continue button. If it does have a value, then show the button. This also works if they at first upload a file and then they try to upload a different file and click cancel.
Here is the code.
HTML:
<div class="container">
<div class="row">
<input class="file-input" type="file" accept="image/*" name="fileUpload" id="fileUpload" capture="camera">
<label for="fileUpload" id="file-upload-btn">Capture or Upload Photo</label>
</div>
<div class="row padding-top-two-em">
<input class="btn btn-success hidden" id="accept-btn" type="submit" value="Accept & Continue"/>
<button class="btn btn-danger">Back</button>
</div></div>
JavaScript:
$('#fileUpload').change(function () {
var fileName = $('#fileUpload').val();
if (fileName != "") {
$('#file-upload-btn').html(fileName);
$('#accept-btn').removeClass('hidden').addClass('show');
} else {
$('#file-upload-btn').html("Upload File");
$('#accept-btn').addClass('hidden');
}
});
CSS:
.file-input {
width: 0.1px;
height: 0.1px;
opacity: 0;
overflow: hidden;
position: absolute;
z-index: -1;
}
.file-input + label {
font-size: 1.25em;
font-weight: normal;
color: white;
background-color: blue;
display: inline-block;
padding: 5px;
}
.file-input:focus + label,
.file-input + label:hover {
background-color: red;
}
.file-input + label {
cursor: pointer;
}
.file-input + label * {
pointer-events: none;
}
For the CSS a lot of this is to make the website and button accessible for everyone. Style your button to whatever you like.
The following seems to work for me (on desktop, windows):
var openFile = function (mimeType, fileExtension) {
var defer = $q.defer();
var uploadInput = document.createElement("input");
uploadInput.type = 'file';
uploadInput.accept = '.' + fileExtension + ',' + mimeType;
var hasActivated = false;
var hasChangedBeenCalled = false;
var hasFocusBeenCalled = false;
var focusCallback = function () {
if (hasActivated) {
hasFocusBeenCalled = true;
document.removeEventListener('focus', focusCallback, true);
setTimeout(function () {
if (!hasChangedBeenCalled) {
uploadInput.removeEventListener('change', changedCallback, true);
defer.resolve(null);
}
}, 300);
}
};
var changedCallback = function () {
uploadInput.removeEventListener('change', changedCallback, true);
if (!hasFocusBeenCalled) {
document.removeEventListener('focus', focusCallback, true);
}
hasChangedBeenCalled = true;
if (uploadInput.files.length === 1) {
//File picked
var reader = new FileReader();
reader.onload = function (e) {
defer.resolve(e.target.result);
};
reader.readAsText(uploadInput.files[0]);
}
else {
defer.resolve(null);
}
};
document.addEventListener('focus', focusCallback, true); //Detect cancel
uploadInput.addEventListener('change', changedCallback, true); //Detect when a file is picked
uploadInput.click();
hasActivated = true;
return defer.promise;
}
This does use angularjs $q but you should be able to replace it with any other promise framework if needed.
Tested on IE11, Edge, Chrome, Firefox, but it does not seem to work on Chrome on a Android Tablet as it does not fire the Focus event.
The file-type field, frustratingly, doesn't respond to a lot of events (blur would be lovely). I see a lot of people suggesting change-oriented solutions and them getting downvoted.
change does work, but it has a major flaw (vs what we want to happen).
When you freshly load a page containing a file field, open the box and press cancel. Nothing, frustratingly, changes.
What I chose to do is load in a gated-state.
The next part of the form a section#after-image in my case is hidden from view. When my file field changes, an upload button is shown. Upon successful upload, section#after-image is shown.
If the user loads, opens the file-dialog, then cancels out, they never see the upload button.
If the user chooses a file, the upload button is shown. If they then open the dialog and cancel, the change event is triggered by this cancel, and there I can (and do) re-hide my upload button until a proper file is selected.
I was fortunate that this gated-state was already the design of my form. You do not need to use the same style, merely having the upload button initially hidden and upon change, setting a hidden field or javascript variable to something you can monitor on submit.
I tried changing the value of files[0] before the field was interacted with. This didn't do anything regarding onchange.
So yes, change works, at least as good as we're going to get. The filefield is secured, for obvious reasons, but to the frustration of well-intentioned developers.
It's not fitting to my purpose, but you might be able to, onclick, load a warning prompt (not an alert(), because that stalls page-processing), and hide it if change is triggered and files[0] is null. If change is not triggered, the div remains in its state.
Solution for file selection with hidden input
Note: this code doesn't detect cancellation, it offers a way to circumvent the need to detect it in a common case in which people try to detect it.
I got here while looking for a solution for file uploads using a hidden input, I believe that this is the most common reason to look for a way to detect cancellation of file input (open file dialog -> if a file was selected then run some code, otherwise do nothing), here's my solution:
var fileSelectorResolve;
var fileSelector = document.createElement('input');
fileSelector.setAttribute('type', 'file');
fileSelector.addEventListener('input', function(){
fileSelectorResolve(this.files[0]);
fileSelectorResolve = null;
fileSelector.value = '';
});
function selectFile(){
if(fileSelectorResolve){
fileSelectorResolve();
fileSelectorResolve = null;
}
return new Promise(function(resolve){
fileSelectorResolve = resolve;
fileSelector.dispatchEvent(new MouseEvent('click'));
});
}
Usage example:
Note that if no file was selected then the first line will return only once selectFile() is called again (or if you called fileSelectorResolve() from elsewhere).
async function logFileName(){
const file = await selectFile();
if(!file) return;
console.log(file.name);
}
Another example:
async function uploadFile(){
const file = await selectFile();
if(!file) return;
// ... make an ajax call here to upload the file ...
}
There is a hackish way to do this (add callbacks or resolve some deferred/promise implementation instead of alert() calls):
var result = null;
$('<input type="file" />')
.on('change', function () {
result = this.files[0];
alert('selected!');
})
.click();
setTimeout(function () {
$(document).one('mousemove', function () {
if (!result) {
alert('cancelled');
}
});
}, 1000);
How it works: while file selection dialog is open, document does not receive mouse pointer events. There is 1000ms delay to allow the dialog to actually appear and block browser window. Checked in Chrome and Firefox (Windows only).
But this is not a reliable way to detect cancelled dialog, of course. Though, might improve some UI behavior for you.
Here is my solution, using the file input focus (not using any timers)
var fileInputSelectionInitiated = false;
function fileInputAnimationStart() {
fileInputSelectionInitiated = true;
if (!$("#image-selector-area-icon").hasClass("fa-spin"))
$("#image-selector-area-icon").addClass("fa-spin");
if (!$("#image-selector-button-icon").hasClass("fa-spin"))
$("#image-selector-button-icon").addClass("fa-spin");
}
function fileInputAnimationStop() {
fileInputSelectionInitiated = false;
if ($("#image-selector-area-icon").hasClass("fa-spin"))
$("#image-selector-area-icon").removeClass("fa-spin");
if ($("#image-selector-button-icon").hasClass("fa-spin"))
$("#image-selector-button-icon").removeClass("fa-spin");
}
$("#image-selector-area-wrapper").click(function (e) {
$("#fileinput").focus();
$("#fileinput").click();
});
$("#preview-image-wrapper").click(function (e) {
$("#fileinput").focus();
$("#fileinput").click();
});
$("#fileinput").click(function (e) {
fileInputAnimationStart();
});
$("#fileinput").focus(function (e) {
fileInputAnimationStop();
});
$("#fileinput").change(function(e) {
// ...
}
Well, this doesn't exactly answers your question. My assumption is that, you have a scenario, when you add a file input, and invoke file selection, and if user hits cancel, you just remove the input.
If this is the case, then: Why adding empty file input?
Create the one on the fly, but add it to DOM only when it is filled in. Like so:
var fileInput = $("<input type='file' name='files' style='display: none' />");
fileInput.bind("change", function() {
if (fileInput.val() !== null) {
// if has value add it to DOM
$("#files").append(fileInput);
}
}).click();
So here I create <input type="file" /> on the fly, bind to it's change event and then immediately invoke click. On change will fire only when user selects a file and hits Ok, otherwise input will not be added to DOM, therefore will not be submitted.
Working example here: https://jsfiddle.net/69g0Lxno/3/
//Use hover instead of blur
var fileInput = $("#fileInput");
if (fileInput.is(":hover") {
//open
} else {
}
function file_click() {
document.body.onfocus = () => {
setTimeout(_=>{
let file_input = document.getElementById('file_input');
if (!file_input.value) alert('please choose file ')
else alert(file_input.value)
document.body.onfocus = null
},100)
}
}
Using setTimeout to get the certain value of the input.
If you already require JQuery, this solution might do the work (this is the exact same code I actually needed in my case, although using a Promise is just to force the code to wait until file selection has been resolved):
await new Promise(resolve => {
const input = $("<input type='file'/>");
input.on('change', function() {
resolve($(this).val());
});
$('body').one('focus', '*', e => {
resolve(null);
e.stopPropagation();
});
input.click();
});
There are several proposed solutions in this thread and this difficulty to detecting when the user clicks the "Cancel" button on the file selection box is a problem that affects many people.
The fact is that there is no 100% reliable way to detect if the user has clicked the "Cancel" button on the file selection box. But there are ways to reliably detect if the user has added a file to the input file. So this is the basic strategy of this answer!
I decided to add this answer because apparently the other answers don't work on most browsers or guaranteed on mobile devices.
Briefly the code is based on 3 points:
The input file is initially created dynamically in "memory" in js
(we don't add it to the "HTML" at this moment);
After adding the file then the input file is added to the HTML, otherwise nothing occurs;
The removal of the file is done by removing the input file from the
HTML by a specific event, which means that the
"editing"/"modification" of the file is done by removing the old
input file and creating a new one.
For a better understanding look at the code below and the notes as well.
[...]
<button type="button" onclick="addIptFl();">ADD INPUT FILE!</button>
<span id="ipt_fl_parent"></span>
[...]
function dynIptFl(jqElInst, funcsObj) {
if (typeof funcsObj === "undefined" || funcsObj === "") {
funcsObj = {};
}
if (funcsObj.hasOwnProperty("before")) {
if (!funcsObj["before"].hasOwnProperty("args")) {
funcsObj["before"]["args"] = [];
}
funcsObj["before"]["func"].apply(this, funcsObj["before"]["args"]);
}
var jqElInstFl = jqElInst.find("input[type=file]");
// NOTE: Open the file selection box via js. By Questor
jqElInstFl.trigger("click");
// NOTE: This event is triggered if the user selects a file. By Questor
jqElInstFl.on("change", {funcsObj: funcsObj}, function(e) {
// NOTE: With the strategy below we avoid problems with other unwanted events
// that may be associated with the DOM element. By Questor
e.preventDefault();
var funcsObj = e.data.funcsObj;
if (funcsObj.hasOwnProperty("after")) {
if (!funcsObj["after"].hasOwnProperty("args")) {
funcsObj["after"]["args"] = [];
}
funcsObj["after"]["func"].apply(this, funcsObj["after"]["args"]);
}
});
}
function remIptFl() {
// NOTE: Remove the input file. By Questor
$("#ipt_fl_parent").empty();
}
function addIptFl() {
function addBefore(someArgs0, someArgs1) {
// NOTE: All the logic here happens just before the file selection box opens.
// By Questor
// SOME CODE HERE!
}
function addAfter(someArgs0, someArgs1) {
// NOTE: All the logic here happens only if the user adds a file. By Questor
// SOME CODE HERE!
$("#ipt_fl_parent").prepend(jqElInst);
}
// NOTE: The input file is hidden as all manipulation must be done via js.
// By Questor
var jqElInst = $('\
<span>\
<button type="button" onclick="remIptFl();">REMOVE INPUT FILE!</button>\
<input type="file" name="input_fl_nm" style="display: block;">\
</span>\
');
var funcsObj = {
before: {
func: addBefore,
args: [someArgs0, someArgs1]
},
after: {
func: addAfter,
// NOTE: The instance with the input file ("jqElInst") could be passed
// here instead of using the context of the "addIptFl()" function. That
// way "addBefore()" and "addAfter()" will not need to be inside "addIptFl()",
// for example. By Questor
args: [someArgs0, someArgs1]
}
};
dynIptFl(jqElInst, funcsObj);
}
Thanks! =D
We achieved in angular like below.
bind click event on input type file.
Attach focus event with window and add condition if uploadPanel is true then show console.
when click on input type file the boolean uploadPanel value is true. and dialogue box appear.
when cancel OR Esc button click then dialogue box dispensary and console appear.
HTML
<input type="file" formControlName="FileUpload" click)="handleFileInput($event.target.files)" />
/>
TS
this.uploadPanel = false;
handleFileInput(files: FileList) {
this.fileToUpload = files.item(0);
console.log("ggg" + files);
this.uploadPanel = true;
}
#HostListener("window:focus", ["$event"])
onFocus(event: FocusEvent): void {
if (this.uploadPanel == true) {
console.log("cancel clicked")
this.addSlot
.get("FileUpload")
.setValidators([
Validators.required,
FileValidator.validate,
requiredFileType("png")
]);
this.addSlot.get("FileUpload").updateValueAndValidity();
}
}
Just add 'change' listener on your input whose type is file. i.e
<input type="file" id="file_to_upload" name="file_to_upload" />
I have done using jQuery and obviously anyone can use valina JS (as per the requirement).
$("#file_to_upload").change(function() {
if (this.files.length) {
alert('file choosen');
} else {
alert('file NOT choosen');
}
});