The simplest solution is to use jQuery to detect all active JavaScript event handlers.
Example
You can try to run the following code to detect active event handlers
Live Demo
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<script>
var myEvent = $("#demo");
myEvent.mouseover(function() {});
$.each(myEvent.data("events"), function(i, e) {
alert(i);
});
</script>
</head>
<body>
<div id = "demo">Demo Text</div>
</body>
</html>