Let's say someone is writing a reply to an online forum on their iPhone when they lose connection.
Is it possible to use HTML5 local storage to save their submission and post it when they get connection back?
If so, how do I tell if the phone has a connection or not?
Yes you can by implementing your custom logic into the app.
To see if a connection is available you could either use navigator.onLine flag (but it seems that is not completely reliable):
Does Safari and/or WebKit implement the equivalent of window.navigator.online?
http://html5demos.com/offline
or try to load content from the internet and see if it's possible or not:
Checking online status from an iPhone web app
Could you not use JavaScript to set a variable and make it a string with the content of whatever the user puts in the box? You could use getElementById or similar to get the content from the form.
Then, store it in a "cookie". If you don't know how to do this, here is a quick run down on javascript cookies from w3: http://www.w3schools.com/js/js_cookies.asp
Then on page load you could have it load the cookie and make the value of the form equal to the variable you declared earlier.
The best approach (in the light of navigator.onLine behaving inconsistently in different browsers) would be to save whatever the user is typing to localStorage every few seconds or every few keystrokes.
If the page is reloaded again, then you can make sure to first see if there is anything stored in the localStorage key, and if so, then load that into the text box and the user can continue from where he left off.
You can also take a look at the 'going offline with web storage' section of this article http://dev.opera.com/articles/view/taking-your-web-apps-offline-web-storage-appcache-websql/
Related
UPDATE: At time of asking this question, this was related to SignalR library and not plain WebSockets. I see correctly formatted messages now.
Is there any way to word-wrap messages in WS tab in Chrome Developer Tools or display JSON with formatting ? It's really annoying to scroll to right to see whole message.
Example with message selected and it's preview doesn't have any formatting or word wrapping applied:
Thank you in advance.
It's working fine here on Chrome/78.0.3904.97:
What I did:
Go to http://crawl.develz.org/play.htm
Open one of the listed servers
Start devtools
Go to the Application tab and add a cookie called "no-compression" with value "yeah no" to the relevant server. (Any truthy string should work, I just chose the least confusing one I could think of in about a minute.)
Otherwise, crawl's webtiles server can end up compressing messages even when browser supports RFC 7692's "permessage-deflate" extension, which ruins the demonstration.
Open the Network tab
Reload the page
Select the "socket" request, switch to the "Messages" tab, and pick a frame.
Start drilling down in the tree view in the bottom pane!
I'm trying to embed a value into the textbox at the USCIS government website to check my application status number. Suppose it's LIN1234. After inspecting the element of the webpage I see that the HTML wrapper for the textbox is:
<input id="receipt_number" name="appReceiptNum" class="form-control textbox initial-focus" maxlength="13" type="text">
I tried opening up this URL with a suffix added on, but to no avail:
https://egov.uscis.gov/casestatus/landing.do?receipt_num=LIN1234
Is there a way to to this?
Before that, you must understand what means adding ?receipt_num=LIN1234 to the url.
When sending a request (By default and in this context) from your browser, it'll be a GET request (see here) where you send as a get argument your receipt number, setting its key to receipt_num.
What is done to this data on the server side, however, is up to itself.
Just understand that unless the server is made to auto-fill the field with that value in case it receives it, it won't do anything except sending some more data.
I think you want to load this page in your browser with auto-filled field.
In that case you should look into extensions for your browser that would do that automatically.
You probably won't be able to embed a value into the textbox... Just because you are sending values by GET (which is what the landing.do?receipt_num=LIN1234 syntax is doing) doesn't mean that they have something set up to process it, so the GET variable will probably not do anything.
You might be able to see how their URLs work ordinarily, what the page URL that you are aiming to land on looks like, and either decode something from that or set a bookmark there. That said, if they are submitting that data via POST (which they probably are, for security reasons), that probably won't work.
I would suggest looking at reputable form-filling plugins for your web browser, if that's an option. That might allow you to work around that.
I've noticed that browsers don't recognize my password field as a potential auto-complete target. I'm assuming this has something to do with the fact that the password field isn't in the original HTML - it's created by my GWT script after the page has loaded.
Is there a way to tell a browser, "hey, here's this form, treat it like usual?" How can I let browsers hook into my app for autofill?
There are some workarounds to get the browser to auto-complete your login like the one described here.
After struggling some time with it I strongly suggest you simply wrap an existing form of your host page (do not generate the inputs with GWT), do a form.submit() on it and have a servlet listen to the request.
I believe that password fields ( tags with type="password") are not auto-filled for fairly obvious security reasons. It doesn't matter that the field is added after page load by your GWT script.
Try mimicking the field in regular HTML and compare that to how your GWT app creates the DOM structure. Perhaps your GWT app is putting the page together differently?
Is there some secret and mystical way to change the value of my HTTP-request's referer, or at the very least, keep it from showing? Also, using a MitM page from another domain would not solve my issue, as you are now just submitting that other page's value.
This is not browser specific, I would need to do this on the HTML level.
The problem I am facing is a silent-login page where it sends an HTTP-Redirect to the http-Referrer, unless it is the same domain, or empty.
You can not control this on an html level. Your only option is to modify the login code to not issue the redirect or to direct it to the desired page.
It's an old question, but I know how you can do this. The first way is not guaranteed across all browsers, but you can use rel=noreferrer. AFAIK GC is the only UA to currently support this but it is in the standard. FX may also, IDK.
The second way is far more reliable, and it involves a cool little hack someone shared with me on IRC:
Basically, construct an iframe from a base64-encoded data: URI. The framed document is to have a script that listens for a window.postMessage() and when it gets fed the command with a URL to visit, it executes window.top.location = msg.data.URI or however it is that one reads the message. Sorry I can't recall, I haven't slept for a few days.
Enjoy if you still care.. :)
How can i limit my form to only accept jpeg files? Now it shows all files.
<input name="image" type="file" />
And are there any javascript method to show progress?
There is an accept attribute in the input tag, but it's not supported by all browsers. Here's an example:
<input type="file" name="image" id="image" accept="image/jpeg" />
It could be your first check, but your main check must be on the server when accepting the file.
How can i limit my form to only accept jpeg files
Mostly, you can't. You have to check at the server (which you need to do anyway, even if you can check at the client; you can never trust client-side validation, of anything). But things are improving. There is the new File API from the W3C coming down-the-pike, which you could use on browsers that support it (Mostly Firefox, at the moment; it was a Mozilla initiative), just for a better user experience for those with modern browsers.
Edit And Gert G points out that here's the accept attribute that can give a hint to the browser, which is nice for browsers that support it.
And are there any javascript method to show progress?
Not directly, no. It's sometimes possible to show progress indirectly, by using a timed series of ajax requests alongside the upload and having the server tell you how much it had received so far, but it's fraught with difficulty and probably not worth the bother.
This is another area where the file API could help, although you might find you introduced a fair bit of latency in the process: Basically, you could read a chunk of the file locally, send that to the server via ajax, update progress, read and send the next chunk, etc.
There are, of course, Flash uploaders like SWFUpload that show progress and such, if you want to use something proprietary (but incredibly widespread). (Flash, I mean.)
There is no pure html way to show certain file types, and there is no easy javascript way either.
I use a package called FancyUpload: http://digitarald.de/project/fancyupload/ which handles this part for me. Also, it will show the download progress bar as you've asked.
I should mention that the uploader I posted needs you to include a javascript framework called MooTools. There are other similar uploaders available if you prefer jQuery (such as uploadify) or another framework.
Please, make sure that you also check on the server side.
This can't be done in plain HTML/Javascript, but there are several Flash-based components that can do this - e.g. Uploadify comes to mind.
If you can live with this limitation, there's plenty of questions about this (with good answers) here on SO.
You can use <input name="image" type="file" accept="image/jpeg"> to limit the users choice. But you still need to check the file type in the server.
You can obviously not display progress without starting the upload, so you should be first looking for a server side api that keep the client updated on the state of the upload. As for javascirpt progress bars every javascript library has one e.g. jquery progress bar