主要是在内存泄漏上的改进
(function() {
window.EventUtils = {
eventFuncs : [],
addEvent : function(o, n, f) {
var el, id;
// Resolve element by id if needed
o = typeof(o) == 'string' ? document.getElementById(o) : o;
if (o.attachEvent) {
// Since we can't use attachEvent we need to generate an unique id for the object
// and place functions in an array one for each object
el = EventUtils.eventFuncs;
id = o._evtID;
if (!el[id]) {
// Generate new unique id
id = o._evtID = el.length;
// Add event listener old fashion way instead of attachEvent
o['on' + n] = function() {
var i, l, e = window.event, li;
e.target = e.srcElement; // Force W3C style
// Execute each event listener in order
for (i = 0, li = el[e.target._evtID], l = li.length; i < l; i++)
li[i](e);
};
// Create array with first function
el[id] = [f];
} else
el[id].push(f); // Push in more functions
// Fix the IE leak
o = null;
} else if (o.addEventListener)
o.addEventListener(n, f, false);
else
o['on' + n] = f;
return f;
},
removeEvent : function(o, n, f) {
var i, li;
// Resolve element by id if needed
o = typeof(o) == 'string' ? document.getElementById(o) : o;
if (o.detachEvent) {
li = EventUtils.eventFuncs[o._evtID];
if (li) {
// Detach event listener by looking for it and remove it from the array
for (i = 0; i < li.length; i++) {
if (li[i] === f)
li.splice(i, 1);
}
}
} else if (o.removeEventListener)
o.removeEventListener(n, f, false);
else
o['on' + n] = null;
}
};
})();