Chrome extension inject javascript before body finish loading

Question

I'm triyng to create a Chrome extension that block a script before it is executed.

The script tag is in body tag and not in head.

Is it possible to do so?

in manifest.json I have set content_scripts like this:

"content_scripts": [
{
 "run_at": "document_start",
 "matches": ["http://website.it/*"],
 "js": ["dojob.js"]
}]

And my script is this one:

var cont = 0;
document.addEventListener("DOMNodeInserted", function(event){
 if(cont==0){
 alert(document.getElementsByTagName("script")[0].src);
 document.getElementsByTagName("script")[0].src = "";
 cont++;
 }
});

But the script still runs...

How cant I make it work?

Answer 1

Since your making src="" I take it that the js is external. If thats the case then you could use the beforeload event or webrequest api to block the loading of the script.

function doBeforeLoad(event){
 if (event.srcElement.tagName=="SCRIPT" && event.srcElement.src=='test.js') {
 event.preventDefault();
 }
}
document.addEventListener('beforeload', doBeforeLoad , true);

http://code.google.com/chrome/extensions/webRequest.html

• Rob W: Make sure that the Content script is executed at document_start, via run_at. For documentation of the beforeload extension event, see stackoverflow.com/q/4395525