Custom Event in browser JavaScript

fireEvent.js

// tested only in safari. Use at your own risk.

Element.prototype.fireEvent = function(a,b) {
	b = b || {};
	b.type = a;
	b.source = this;
	var evt = document.createEvent("Events");
	evt.initEvent(a, true, true);
	for(var i in b){
		if(b){ evt[i] = b[i]; }
	}
	evt.value = b;
	this.dispatchEvent(evt);
};

//======== Example =========

var btn = document.createElement('button');

btn.addEventListener('pedro', function(e){
	alert(e.hello); // alerts "world"
});

btn.addEventListener('click', function(){
	btn.fireEvent('pedro', { hello: 'world' });
});