I'm writing a Chrome extension and trying to overlay a <div> over the current webpage as soon as a button is clicked in the popup.html file.
When I access the document.body.insertBefore method from within popup.html it overlays the <div> on the popup, rather than the current webpage.
Do I have to use messaging between background.html and popup.html in order to access the web page's DOM? I would like to do everything in popup.html, and to use jQuery too, if possible.
ManifestV3 service worker doesn't have any DOM/document/window.
ManifestV3/V2 extension pages (and the scripts inside) have their own DOM, document, window, and a chrome-extension:// URL (use devtools for that part of the extension to inspect it).
You need a content script to access DOM of web pages and interact with a tab's contents. Content scripts will execute in the tab as a part of that page, not as a part of the extension, so don't load your content script(s) in the extension page, use the following methods:
Method 1. Declarative
manifest.json:
"content_scripts": [{
"matches": ["*://*.example.com/*"],
"js": ["contentScript.js"]
}],
It will run once when the page loads. After that happens, use messaging but note, it can't send DOM elements, Map, Set, ArrayBuffer, classes, functions, and so on - it can only send JSON-compatible simple objects and types so you'll need to manually extract the required data and pass it as a simple array or object.
Method 2. Programmatic
ManifestV2:
Use chrome.tabs.executeScript in the extension script (like the popup or background) to inject a content script into a tab on demand.
The callback of this method receives results of the last expression in the content script so it can be used to extract data which must be JSON-compatible, see method 1 note above.
Required permissions in manifest.json:
Best case: "activeTab", suitable for a response to a user action (usually a click on the extension icon in the toolbar). Doesn't show a permission warning when installing the extension.
Usual: "*://*.example.com/" plus any other sites you want.
Worst case: "<all_urls>" or "*://*/", "http://*/", "https://*/" - when submitting into Chrome Web Store all of these put your extension in a super slow review queue because of broad host permissions.
ManifestV3 differences to the above:
Use chrome.scripting.executeScript.
Required permissions in manifest.json:
"scripting" - mandatory
"activeTab" - ideal scenario, see notes for ManifestV2 above.
If ideal scenario is impossible add the allowed sites to host_permissions in manifest.json.
Some examples of the extension popup script that use programmatic injection to add that div.
ManifestV3
Don't forget to add the permissions in manifest.json, see the other answer for more info.
Simple call:
(async () => {
const [tab] = await chrome.tabs.query({active: true, currentWindow: true});
await chrome.scripting.executeScript({
target: {tabId: tab.id},
func: inContent1,
});
})();
// executeScript runs this code inside the tab
function inContent1() {
const el = document.createElement('div');
el.style.cssText = 'position:fixed; top:0; left:0; right:0; background:red';
el.textContent = 'DIV';
document.body.appendChild(el);
}
Note: in Chrome 91 or older func: should be function:.
Calling with parameters and receiving a result
Requires Chrome 92 as it implemented args.
Example 1:
res = await chrome.scripting.executeScript({
target: {tabId: tab.id},
func: (a, b) => { return [window[a], window[b]]; },
args: ['foo', 'bar'],
});
Example 2:
(async () => {
const [tab] = await chrome.tabs.query({active: true, currentWindow: true});
let res;
try {
res = await chrome.scripting.executeScript({
target: {tabId: tab.id},
func: inContent2,
args: [{ foo: 'bar' }], // arguments must be JSON-serializable
});
} catch (e) {
console.warn(e.message || e);
return;
}
// res[0] contains results for the main page of the tab
document.body.textContent = JSON.stringify(res[0].result);
})();
// executeScript runs this code inside the tab
function inContent2(params) {
const el = document.createElement('div');
el.style.cssText = 'position:fixed; top:0; left:0; right:0; background:red';
el.textContent = params.foo;
document.body.appendChild(el);
return {
success: true,
html: document.body.innerHTML,
};
}
ManifestV2
Simple call:
// uses inContent1 from ManifestV3 example above
chrome.tabs.executeScript({ code: `(${ inContent1 })()` });
Calling with parameters and receiving a result:
// uses inContent2 from ManifestV3 example above
chrome.tabs.executeScript({
code: `(${ inContent2 })(${ JSON.stringify({ foo: 'bar' }) })`
}, ([result] = []) => {
if (!chrome.runtime.lastError) {
console.log(result); // shown in devtools of the popup window
}
});
This example uses automatic conversion of inContent function's code to string, the benefit here is that IDE can apply syntax highlight and linting. The obvious drawback is that the browser wastes time to parse the code, but usually it's less than 1 millisecond thus negligible.
I am in the process of building a Chrome extension, and for the whole thing to work the way I would like it to, I need an external JavaScript script to be able to detect if a user has my extension installed.
For example: A user installs my plugin, then goes to a website with my script on it. The website detects that my extension is installed and updates the page accordingly.
Is this possible?
Chrome now has the ability to send messages from the website to the extension.
So in the extension background.js (content.js will not work) add something like:
chrome.runtime.onMessageExternal.addListener(
function(request, sender, sendResponse) {
if (request) {
if (request.message) {
if (request.message == "version") {
sendResponse({version: 1.0});
}
}
}
return true;
});
This will then let you make a call from the website:
var hasExtension = false;
chrome.runtime.sendMessage(extensionId, { message: "version" },
function (reply) {
if (reply) {
if (reply.version) {
if (reply.version >= requiredVersion) {
hasExtension = true;
}
}
}
else {
hasExtension = false;
}
});
You can then check the hasExtension variable. The only drawback is the call is asynchronous, so you have to work around that somehow.
Edit:
As mentioned below, you'll need to add an entry to the manifest.json listing the domains that can message your addon. Eg:
"externally_connectable": {
"matches": ["*://localhost/*", "*://your.domain.com/*"]
},
2021 Update:
chrome.runtime.sendMessage will throw the following exception in console if the extension isn't installed or it's disabled.
Unchecked runtime.lastError: Could not establish connection. Receiving end does not exist
To fix this, add this validation inside the sendMessage callback
if (chrome.runtime.lastError) {
// handle error
}
I am sure there is a direct way (calling functions on your extension directly, or by using the JS classes for extensions), but an indirect method (until something better comes along):
Have your Chrome extension look for a specific DIV or other element on your page, with a very specific ID.
For example:
<div id="ExtensionCheck_JamesEggersAwesomeExtension"></div>
Do a getElementById and set the innerHTML to the version number of your extension or something. You can then read the contents of that client-side.
Again though, you should use a direct method if there is one available.
EDIT: Direct method found!!
Use the connection methods found here: https://developer.chrome.com/extensions/extension#global-events
Untested, but you should be able to do...
var myPort=chrome.extension.connect('yourextensionid_qwerqweroijwefoijwef', some_object_to_send_on_connect);
Another method is to expose a web-accessible resource, though this will allow any website to test if your extension is installed.
Suppose your extension's ID is aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa, and you add a file (say, a transparent pixel image) as test.png in your extension's files.
Then, you expose this file to the web pages with web_accessible_resources manifest key:
"web_accessible_resources": [
"test.png"
],
In your web page, you can try to load this file by its full URL (in an <img> tag, via XHR, or in any other way):
chrome-extension://aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa/test.png
If the file loads, then the extension is installed. If there's an error while loading this file, then the extension is not installed.
// Code from https://groups.google.com/a/chromium.org/d/msg/chromium-extensions/8ArcsWMBaM4/2GKwVOZm1qMJ
function detectExtension(extensionId, callback) {
var img;
img = new Image();
img.src = "chrome-extension://" + extensionId + "/test.png";
img.onload = function() {
callback(true);
};
img.onerror = function() {
callback(false);
};
}
Of note: if there is an error while loading this file, said network stack error will appear in the console with no possibility to silence it. When Chromecast used this method, it caused quite a bit of controversy because of this; with the eventual very ugly solution of simply blacklisting very specific errors from Dev Tools altogether by the Chrome team.
Important note: this method will not work in Firefox WebExtensions. Web-accessible resources inherently expose the extension to fingerprinting, since the URL is predictable by knowing the ID. Firefox decided to close that hole by assigning an instance-specific random URL to web accessible resources:
The files will then be available using a URL like:
moz-extension://<random-UUID>/<path/to/resource>
This UUID is randomly generated for every browser instance and is not your extension's ID. This prevents websites from fingerprinting the extensions a user has installed.
However, while the extension can use runtime.getURL() to obtain this address, you can't hard-code it in your website.
I thought I would share my research on this.
I needed to be able to detect if a specific extension was installed for some file:/// links to work.
I came across this article here
This explained a method of getting the manifest.json of an extension.
I adjusted the code a bit and came up with:
function Ext_Detect_NotInstalled(ExtName, ExtID) {
console.log(ExtName + ' Not Installed');
if (divAnnounce.innerHTML != '')
divAnnounce.innerHTML = divAnnounce.innerHTML + "<BR>"
divAnnounce.innerHTML = divAnnounce.innerHTML + 'Page needs ' + ExtName + ' Extension -- to intall the LocalLinks extension click here';
}
function Ext_Detect_Installed(ExtName, ExtID) {
console.log(ExtName + ' Installed');
}
var Ext_Detect = function (ExtName, ExtID) {
var s = document.createElement('script');
s.onload = function () { Ext_Detect_Installed(ExtName, ExtID); };
s.onerror = function () { Ext_Detect_NotInstalled(ExtName, ExtID); };
s.src = 'chrome-extension://' + ExtID + '/manifest.json';
document.body.appendChild(s);
}
var is_chrome = navigator.userAgent.toLowerCase().indexOf('chrome') > -1;
if (is_chrome == true) {
window.onload = function () { Ext_Detect('LocalLinks', 'jllpkdkcdjndhggodimiphkghogcpida'); };
}
With this you should be able to use Ext_Detect(ExtensionName,ExtensionID) to detect the installation of any number of extensions.
Another possible solution if you own the website is to use inline installation.
if (chrome.app.isInstalled) {
// extension is installed.
}
I know this an old question but this way was introduced in Chrome 15 and so I thought Id list it for anyone only now looking for an answer.
Here is an other modern approach:
const checkExtension = (id, src, callback) => {
let e = new Image()
e.src = 'chrome-extension://'+ id +'/'+ src
e.onload = () => callback(1), e.onerror = () => callback(0)
}
// "src" must be included to "web_accessible_resources" in manifest.json
checkExtension('gighmmpiobklfepjocnamgkkbiglidom', 'icons/icon24.png', (ok) => {
console.log('AdBlock: %s', ok ? 'installed' : 'not installed')
})
checkExtension('bhlhnicpbhignbdhedgjhgdocnmhomnp', 'images/checkmark-icon.png', (ok) => {
console.log('ColorZilla: %s', ok ? 'installed' : 'not installed')
})
I used the cookie method:
In my manifest.js file I included a content script that only runs on my site:
"content_scripts": [
{
"matches": [
"*://*.mysite.co/*"
],
"js": ["js/mysite.js"],
"run_at": "document_idle"
}
],
in my js/mysite.js I have one line:
document.cookie = "extension_downloaded=True";
and in my index.html page I look for that cookie.
if (document.cookie.indexOf('extension_downloaded') != -1){
document.getElementById('install-btn').style.display = 'none';
}
You could have the extension set a cookie and have your websites JavaScript check if that cookie is present and update accordingly. This and probably most other methods mentioned here could of course be cirvumvented by the user, unless you try and have the extension create custom cookies depending on timestamps etc, and have your application analyze them server side to see if it really is a user with the extension or someone pretending to have it by modifying his cookies.
There's another method shown at this Google Groups post. In short, you could try detecting whether the extension icon loads successfully. This may be helpful if the extension you're checking for isn't your own.
Webpage interacts with extension through background script.
manifest.json:
"background": {
"scripts": ["background.js"],
"persistent": true
},
"externally_connectable": {
"matches": ["*://(domain.ext)/*"]
},
background.js:
chrome.runtime.onMessageExternal.addListener(function(msg, sender, sendResponse) {
if ((msg.action == "id") && (msg.value == id))
{
sendResponse({id : id});
}
});
page.html:
<script>
var id = "some_ext_id";
chrome.runtime.sendMessage(id, {action: "id", value : id}, function(response) {
if(response && (response.id == id)) //extension installed
{
console.log(response);
}
else //extension not installed
{
console.log("Please consider installig extension");
}
});
</script>
Your extension could interact with the website (e.g. changing variables) and your website could detect this.
But there should be a better way to do this. I wonder how Google is doing it on their extension gallery (already installed applications are marked).
Edit:
The gallery use the chrome.management.get function. Example:
chrome.management.get("mblbciejcodpealifnhfjbdlkedplodp", function(a){console.log(a);});
But you can only access the method from pages with the right permissions.
A lot of the answers here so far are Chrome only or incur an HTTP overhead penalty. The solution that we are using is a little different:
1. Add a new object to the manifest content_scripts list like so:
{
"matches": ["https://www.yoursite.com/*"],
"js": [
"install_notifier.js"
],
"run_at": "document_idle"
}
This will allow the code in install_notifier.js to run on that site (if you didn't already have permissions there).
2. Send a message to every site in the manifest key above.
Add something like this to install_notifier.js (note that this is using a closure to keep the variables from being global, but that's not strictly necessary):
// Dispatch a message to every URL that's in the manifest to say that the extension is
// installed. This allows webpages to take action based on the presence of the
// extension and its version. This is only allowed for a small whitelist of
// domains defined in the manifest.
(function () {
let currentVersion = chrome.runtime.getManifest().version;
window.postMessage({
sender: "my-extension",
message_name: "version",
message: currentVersion
}, "*");
})();
Your message could say anything, but it's useful to send the version so you know what you're dealing with. Then...
3. On your website, listen for that message.
Add this to your website somewhere:
window.addEventListener("message", function (event) {
if (event.source == window &&
event.data.sender &&
event.data.sender === "my-extension" &&
event.data.message_name &&
event.data.message_name === "version") {
console.log("Got the message");
}
});
This works in Firefox and Chrome, and doesn't incur HTTP overhead or manipulate the page.
You could also use a cross-browser method what I have used.
Uses the concept of adding a div.
in your content script (whenever the script loads, it should do this)
if ((window.location.href).includes('*myurl/urlregex*')) {
$('html').addClass('ifextension');
}
in your website you assert something like,
if (!($('html').hasClass('ifextension')){}
And throw appropriate message.
If you have control over the Chrome extension, you can try what I did:
// Inside Chrome extension
var div = document.createElement('div');
div.setAttribute('id', 'myapp-extension-installed-div');
document.getElementsByTagName('body')[0].appendChild(div);
And then:
// On web page that needs to detect extension
if ($('#myapp-extension-installed-div').length) {
}
It feels a little hacky, but I couldn't get the other methods to work, and I worry about Chrome changing its API here. It's doubtful this method will stop working any time soon.
If you're trying to detect any extension from any website,
This post helped: https://ide.hey.network/post/5c3b6c7aa7af38479accc0c7
Basically, the solution would be to simply try to get a specific file (manifest.json or an image) from the extension by specifying its path. Here's what I used. Definitely working:
const imgExists = function(_f, _cb) {
const __i = new Image();
__i.onload = function() {
if (typeof _cb === 'function') {
_cb(true);
}
}
__i.onerror = function() {
if (typeof _cb === 'function') {
_cb(false);
}
}
__i.src = _f;
__i = null;
});
try {
imgExists("chrome-extension://${CHROME_XT_ID}/xt_content/assets/logo.png", function(_test) {
console.log(_test ? 'chrome extension installed !' : 'chrome extension not installed..');
ifrm.xt_chrome = _test;
// use that information
});
} catch (e) {
console.log('ERROR', e)
}
Here is how you can detect a specific Extension installed and show a warning message.
First you need to open the manifest file of the extension by going to chrome-extension://extension_id_here_hkdppipefbchgpohn/manifest.json and look for any file name within "web_accessible_resources" section.
<div class="chromewarning" style="display:none">
<script type="text/javascript">
$.get("chrome-extension://extension_id_here_hkdppipefbchgpohn/filename_found_in_ web_accessible_resources.png").done(function () {
$(".chromewarning").show();
}).fail(function () {
// alert("failed.");
});
</script>
<p>We have detected a browser extension that conflicts with learning modules in this course.</p>
</div>
Chrome Extension Manifest v3:
const isFirefox = chrome.runtime.OnInstalledReason.CHROME_UPDATE != "chrome_update";
For FireFox, I believe chrome.runtime.OnInstalledReason.BROWSER_UPDATE will be "browser_update": https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/runtime/OnInstalledReason
I am building several apps and want to be able to reuse som code as separate HTML pages by passing parameters to them.
I would really like to pass parameters via ajax with one of these:
Alt1
$.mobile.pageContainer.pagecontainer("change", "../Photo/Photo.html", { reload: true, parameter: "dummyParameter"});
$.mobile.changePage("../Photo/Photo.html", { reloadPage: true, parameter: "dummyParameter"});
Problem is that the page wont reload.
If I use the below link the page is loaded/reloaded, but I cant seem to find the passed parameter.
Alt2
Or through a basic link
(I would prefeer to not generate the url in javascript as in alt2 but if what it takes...)
I use this code to try to retreive the parameters:
$(document).on("pagebeforechange", function (e, data) {
if (data.toPage[0].id == "Photo") {
//var parameters = $(this).data("url").split("?")[1];
//var parameter = parameters.replace("paremeter=", "");
var stuff = data.options.stuff;
//showStuff("#p2", stuff);
}
});
While I'm at it, if someone uses type script. Visual studio complains about that this call signature isnt correct:
$(document).on("pagebeforechange", function (e, data)
Expects one argument, the event, not the data. The plugin generates correct javascript but the IDE complains.
Thanks!
I know hat it is possible, but I am not quite sure how to do it the 'right' way, as to ensure there are no conflicts.
I came across this question: Cannot call functions to content scripts by clicking on image . But it is so convoluted with random comments that it's hard to understand what the corrected way was.
Use case:
Html pages have a div on the page where they expect anyone using the Chrome extension to inject a picture. When users click on he picture, I want to somehow notify an event script. So I know I need to register a listener so the code inserted messages the event script.
Can I get some indication on what code to inject through the content script? I saw that sometimes injecting jquery directly is advised.
I am trying to avoid having the html page to post a message to itself so it can be intercepted. Thanks
With the help of Jquery something like this would capture the image onclick event and allow you to pass a message to a background page in the Chrome Extension:
$("img").click(function(){
var imageSrc = $(this).attr("src");
//Post to a background page in the Chrome Extension
chrome.extension.sendMessage({ cmd: "postImage", data: { imgSrc: imageSrc } }, function (response) {
return response;
});
});
Then in your background.js create a listener for the message:
chrome.extension.onMessage.addListener(
function (request, sender, sendResponse) {
if (request.cmd == "postImage") {
var imageSrc = request.data.imgSrc;
}
});
Is there an API to programmatically refresh the current tab from inside a browser action button? I have background page configured, which attaches a listener via:
chrome.browserAction.onClicked.addListener(function(tab) { ... });
So the callback function retrieves a reference to the tab that it was clicked from, but I don't see an API anywhere to refresh/reload that tab.
I think what you're looking for is:
chrome.tabs.reload(integer tabId, object reloadProperties, function callback)
Check out tabs API() documentation for more information.
The API for chrome.tabs.getSelected(), which the accepted answer uses, has been deprecated. You should instead get the current tab and reload it using something like the following:
chrome.tabs.query({active: true, currentWindow: true}, function (arrayOfTabs) {
var code = 'window.location.reload();';
chrome.tabs.executeScript(arrayOfTabs[0].id, {code: code});
});
Or perhaps:
chrome.tabs.query({active: true, currentWindow: true}, function (arrayOfTabs) {
chrome.tabs.reload(arrayOfTabs[0].id);
});
I had no real luck with the second version, though other answers seem to suggest it should work. The API seems to suggest that, too.
I recommend using chrome.tabs.executeScript to inject javascript that calls window.location.reload() into the current tab. Something like:
chrome.tabs.getSelected(null, function(tab) {
var code = 'window.location.reload();';
chrome.tabs.executeScript(tab.id, {code: code});
});
Reference here
More specifically:
chrome.tabs.getSelected(null, function(tab) {
chrome.tabs.reload(tab.id);
});
You can also use this:
chrome.tabs.reload(function(){});
reload function params: integer tabId, object reloadProperties,
function callback
Reference: http://developer.chrome.com/extensions/tabs.html#method-reload
if you want to reload all the tabs which have loaded completely and are active in their window
chrome.tabs.query({status:'complete'}, (tabs)=>{
tabs.forEach((tab)=>{
if(tab.url){
chrome.tabs.update(tab.id,{url: tab.url});
}
});
});
you can change the parameter object to fetch only active tabs as {status:'complete', active: true} refer to query api of chrome extensions
Reason for not using chrome.tabs.reload :
If the tab properties especially the tab.url have not changed, tab does not reload. If you want to force reload every time, it is better to update the tab URL with its own tab.url which sends the event of the change in property and tab automatically reloads.