JavaScript: eventUtility

gistfile1.js

var eventUtility = {
    addEvent: (function () {
        if (typeof addEventListener !== "undefined") {
            return function (obj, evt, fn) {
                obj.addEventListener(evt, fn, false);
            };
        } else {
            return function (obj, evt, fn) {
                obj.attachEvent("on" + evt, fn);
            };
        }
    } ()),

    removeEvent: (function () {
        if (typeof addEventListener !== "undefined") {
            return function (obj, evt, fn) {
                obj.removeEventListener(evt, fn, false);
            };
        } else {
            return function (obj, evt, fn) {
                obj.detachEvent("on" + evt, fn);
            };
        }
    } ()),

    getTarget: (function () {
        if (typeof addEventListener !== "undefined") {
            return function (event) {
                return event.target;
            }
        } else {
            return function (event) {
                return event.srcElement;
            }
        }
    } ()),

    preventDefault: (function () {
        if (typeof addEventListener !== "undefined") {
            return function (event) {
                event.preventDefault();
            }
        } else {
            return function (event) {
                event.returnValue = false;
            }
        }
    } ())
};