EventUtil.js

// Cross Browser Event Utility
// Nicholas Zakas, Professional JavaScript for Web Developers p.441

(function(window, document) {
'use strict';
var
    EventUtil = {
        addHandler: function( element, type, handler ) {
            if ( element.addEventListener ) {
                element.addEventListener ( type, handler, false );
            } else if ( element.attachEvent ) {
                element.attachEvent ( "on" + type, handler );
            } else {
                element["on" + type] = handler;
            }
        },

        getEvent: function ( event ) {
            return event ? event : window.event;
        },

        getTarget: function ( event ) {
            return event.target || event.srcElement;
        },

        preventDefault: function ( event ) {
            if ( event.preventDefault ) {
                event.preventDefault();
            } else {
                event.returnValue = false;
            }
        },

        removeHandler: function( element, type, handler ) {
            if ( element.removeEventListener ) {
                element.removeEventListener ( type, handler, false );
            } else if ( element.detachEvent ) {
                element.detachEvent ( "on" + type, handler );
            } else {
                element["on" + type] = null;
            }
        },

        stopPropagation: function ( event ) {
            if ( event.stopPropagation ) {
                event.stopPropagation();
            } else {
                event.cancelBubble = true;
            }
        }

    };


    var newAnchor = document.createElement( "a" );
    newAnchor.href = "#";
    newAnchor.appendChild ( document.createTextNode("Test Link") );
    document.body.appendChild(newAnchor);

    newAnchor.onclick = function ( event ) {
        var target;

        event = EventUtil.getEvent ( event );
        EventUtil.preventDefault ( event );
        EventUtil.stopPropagation ( event );
        target = EventUtil.getTarget ( event );

        if ( "innerText" in target ) {
            target.innerText = target.innerHTML + 'X';
        } else {
            target.textContent = target.textContent + 'X';
        }
    };

})(window, window.document);