Cross-browser event hookup made easy

I seem to be on a roll. I’m coding and might as well be sharing some of what I’m working on while I do it. In that sense, here goes another small bit of code that I’ll be adding to jsSimple on github.

We all know how to hook up events cross-browser. We know that we have both attachEvent and addEventListener. Both have varying syntax and we’ve all written this code a million times. Let’s just make this simple. Here’s how to call this:

Event.add(element, 'click', callback, false);
// .. 
Event.remove(element, 'click', callback, false);

The remove looks like you’re passing around the same data, so I added a return value to “add” that allows you to capture the event and pass it in as a single object to the remove function as follows:

var evt = Event.add(element, 'click', callback, false);
// .. 
Event.remove(evt);

So, without further delay, here is the object definition:

/*!
 * jsSimple v0.0.1
 * www.jssimple.com
 *
 * Copyright (c) Tobin Titus
 * Available under the BSD and MIT licenses: www.jssimple.com/license/
 */
var EventObj = function (target, type, listener, capture) {
  return {
    'target' : target,
    'type' : type,
    'listener' : listener,
    'capture' : capture
  };
};

var Event = (function() {
  'use strict';
  function add (target, type, listener, capture) {
    capture = capture || false;
    if (target.addEventListener) {
      target.addEventListener(type, listener, capture);
    } else if (target.attachEvent) {
      target.attachEvent("on" + type, listener);
    }
    return new EventObj(target, type, listener, capture);
  }
  
  function remove(object, type, listener, capture) {
    var target;
    if (object && !type && !listener && !capture) {
      type = object.type;
      listener = object.listener;
      capture = object.capture;
      target = object.target;
    } else {
      capture = capture || false;
      target = object;
    }
    
    if (target.removeEventListener) {
      target.removeEventListener(type, listener, capture);
    } else if (target.detachEvent) {
      target.detachEvent("on" + type, listener);
    }
  }
  
  return {
    'add' : add,
    'remove' : remove
  };
}());

You can see this all in action on jsFiddle.

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