Linrstudio · July 27, 2015 05:12
diff --git a/events_spy.js b/events_spy.js
 I have the script events_spy.js: 

 (function(original) { 
        Element.prototype.addEventListener = function(type, listener, 
 useCapture) { 
                if (typeof (this._handlerTypes) == 'undefined') { 
                        this._handlerTypes = {}; 
                } 
                this._handlerTypes[type] = true; 
                return original.apply(this, arguments); 
        } 
 })(Element.prototype.addEventListener); 
 // https://groups.google.com/a/chromium.org/forum/#!topic/chromium-extensions/HZ7j11UlPHk
 (function(original) { 
        Element.prototype.removeEventListener = function(type, listener, 
 useCapture) { 
                if (typeof (this._handlerTypes) != 'undefined') { 
                        delete this._handlerTypes[type]; 
                } 
                return original.apply(this, arguments); 
        } 
 })(Element.prototype.removeEventListener); 

 I declare this script in manifest.json as follows: 

 "content_scripts" : [ 
 { 
        "matches" : [ "http://*/*", "https://*/*" ], 
        "js" : [ "content/events_spy.js" ], 
        "run_at" : "document_start", 
        "all_frames" : true 
 }, 
 ... 
 ] 

 Then I test my extension on the following HTML page: 

 <!DOCTYPE html> 
 <html> 
 <head> 
 </head> 
 <body> 
   <a id="test" href="#">Click here</a> 
   <script type="application/javascript"> 
        document.getElementById("test").addEventListener("click", function() 
 { alert("clicked"); }, false); 
   </script> 
 </body> 
 </html> 

 Unfortunately, this doesn't work - I can't see that debugger stops 
 inside my custom addEventListener() function. What am I doing wrong? 

 Thanks, 
 Michael
	I have the script events_spy.js:

	(function(original) {
	Element.prototype.addEventListener = function(type, listener,
	useCapture) {
	if (typeof (this._handlerTypes) == 'undefined') {
	this._handlerTypes = {};
	}
	this._handlerTypes[type] = true;
	return original.apply(this, arguments);
	}
	})(Element.prototype.addEventListener);
	// https://groups.google.com/a/chromium.org/forum/#!topic/chromium-extensions/HZ7j11UlPHk
	(function(original) {
	Element.prototype.removeEventListener = function(type, listener,
	useCapture) {
	if (typeof (this._handlerTypes) != 'undefined') {
	delete this._handlerTypes[type];
	}
	return original.apply(this, arguments);
	}
	})(Element.prototype.removeEventListener);

	I declare this script in manifest.json as follows:

	"content_scripts" : [
	{
	"matches" : [ "http:///", "https:///" ],
	"js" : [ "content/events_spy.js" ],
	"run_at" : "document_start",
	"all_frames" : true
	},
	...
	]

	Then I test my extension on the following HTML page:

	<!DOCTYPE html>
	<html>
	<head>
	</head>
	<body>
	<a id="test" href="#">Click here</a>
	<script type="application/javascript">
	document.getElementById("test").addEventListener("click", function()
	{ alert("clicked"); }, false);
	</script>
	</body>
	</html>

	Unfortunately, this doesn't work - I can't see that debugger stops
	inside my custom addEventListener() function. What am I doing wrong?

	Thanks,
	Michael