Dead simple wrapper for event functions in JavaScript. Adds addListener and removeListener to the global namespace.

simple_javascript_event_wrapper.js

(function(w) {
    //  Create the Event Function wrappers
    if (w.addEventListener) {
        // standards compliant method
        w.addListener = function(el, eType, fn, capture) {
            el.addEventListener(eType, fn, capture);
        };
        w.removeListener = function (el, eType, fn, capture) {
            el.removeEventListener(eType, fn, capture);
        };
    }
    else if (w.attachEvent) {
        // microsoft compliant method
        w.addListener = function(el, eType, fn, capture) {
            el.attachEvent("on" + eType, fn, capture);
        };
        w.removeListener = function (el, eType, fn, capture) {
            el.detachEvent("on" + eType, fn, capture);
        };
    }
    else {
        // really old browses, circa 1990's
        throw('Event handlers are unsupported in this browser.');
    }
}());