So we came across this need for a consistent Event object. Here, world!

• eventArgs
  • button (int)
  • buttonLeft (bool)
  • buttonRight (bool)
  • buttonMiddle (bool)
  • domEvent (window.event)
  • keyCode (int)
  • charCode (int)  << not sure about this one :(
  • char                << or this :( 
  • offsetX (int)
  • offsetY (int)
  • relatedElement (DOM Element)
  • srcElement (DOM Element)

var EventArgs = function(e, _domElement) {
    var msie = window.navigator.userAgent.toLowerCase().indexOf('msie') > -1;
    if (!e) e = window.event; //msie
    this.domEvent = e;
    this.srcElement = _domElement;
    if (!this.domElement) {
        if (e.srcElement) this.srcElement = e.srcElement;
        else if (e.target) this.srcElement = e.target;
    }
    
    this.button = e.button;
    // use msie's button map as it has more data
    if (!msie &&
        (e.type == "mousedown" ||
         e.type == "mouseup" ||
         e.type == "mousemove")) {
         switch (this.button) {
            case 0:
                this.button = 1; // left
                break;
            case 1:
                this.button = 4; // middle
                break;
            case 2:
                this.button = 2; // right
                break;
         }
    }

    var LEFT = 1;
    var RIGHT = 2;
    var MIDDLE = 4;
    this.buttonLeft = (this.button & LEFT) == LEFT;
    this.buttonRight = (this.button & RIGHT) == RIGHT;
    this.buttonMiddle = (this.button & MIDDLE) == MIDDLE;
   
    this.offsetX = e.offsetX;
    this.offsetY = e.offsetY;
    if (!this.offsetX && !msie && e.layerX) {
        this.offsetX = e.layerX;
        this.offsetY = e.layerY;
    }
    this.relatedElement = e.relatedTarget;
    if (e.type == "mouseover" && !this.relatedElement && msie && e.fromElement) {
        this.relatedElement = e.fromElement;
    }
    if (e.type == "mouseout" && !this.relatedElement && msie && e.toElement) {
        this.relatedElement = e.toElement;
    }
    this.keyCode = e.keyCode;
    this.charCode = e.charCode;
    if (!this.charCode) {
        if (e.shiftKey == false) {
            this.charCode = this.keyCode + 32; // hmmph .. todo: replace this
        } else {
            this.charCode = this.keyCode;  // yuck
        }
    }
    this.char = String.fromCharCode(this.charCode ? this.charCode : this.keyCode);
};

This is a lil wordy but more or less self-documenting.

So where you would normally pass event, instead pass new EventArgs(event). This abstracts away the browser differences based on the model described in the bulleted list at the top of this blog post. :)

<a href="#" onmouseup="doSomething(new EventArgs(event))">click me</a>