javascript - addEventListener("beforeload") missing events - Stack Overflow

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I'm trying to make a simple Chrome Addon to remove every event from domain x. I've looked into it and found out about the "beforeload" event listener, this is apparently what things like adblock use to block ads pletely from loading. I've implemented this into the addon and added things like console.log("addon loaded") to be sure it's actually loading the javascript, but the problem is, it only catches a handful of the events, for instance on a page of 50 events, it catches only maybe 1-2. It misses obvious other things.

twitch.js

document.addEventListener("beforeload", function(event) {
    event.preventDefault();
    $(event.target).remove();
}, true);

manifest.json

...
"content_scripts": [ {
    "js": [ "js/jquery.js", "js/twitch.js" ],
    "css": [ "css/twitch.css"],
    "matches": ["*://*/*"], 
    "run_at": "document_start",
    "all_frames" : true
}],
...

Does anyone have any ideas?

I'm trying to make a simple Chrome Addon to remove every event from domain x. I've looked into it and found out about the "beforeload" event listener, this is apparently what things like adblock use to block ads pletely from loading. I've implemented this into the addon and added things like console.log("addon loaded") to be sure it's actually loading the javascript, but the problem is, it only catches a handful of the events, for instance on a page of 50 events, it catches only maybe 1-2. It misses obvious other things.

twitch.js

document.addEventListener("beforeload", function(event) {
    event.preventDefault();
    $(event.target).remove();
}, true);

manifest.json

...
"content_scripts": [ {
    "js": [ "js/jquery.js", "js/twitch.js" ],
    "css": [ "css/twitch.css"],
    "matches": ["*://*/*"], 
    "run_at": "document_start",
    "all_frames" : true
}],
...

Does anyone have any ideas?

• javascript
• jquery
• google-chrome
• google-chrome-extension

Share Improve this question Follow edited Jul 8, 2012 at 20:57 Wladimir Palant 57.7k1212 gold badges9999 silver badges127127 bronze badges asked Jul 8, 2012 at 20:04 clone1018clone1018 1,26722 gold badges1111 silver badges1313 bronze badges

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1 Answer 1

Sorted by: Reset to default 5

beforeload is called once for each script, iframe, image and stylesheet on the page, not for every event (do you mean element?). Were you expecting other elements to raise this event?

This document, Blocking Unwanted Content, mentions a requirement:

To block content, your script must be run as a Start Script, so that it executes before the content is displayed.

So check that. Also, you don't need the .remove() line, just calling event.preventDefault() will stop the creation of the resource.

document.addEventListener( 'beforeload', function( event ) {
    event.preventDefault();
}, true );

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