创建兼容 IE/FireFox 的 event 及 event 的 srcElement、fromElement、toElement 属性

if(window.addEventListener) { FixPrototypeForGecko(); }

function FixPrototypeForGecko()
{
HTMLElement.prototype.__defineGetter__("runtimeStyle",element_prototype_get_runtimeStyle);
window.constructor.prototype.__defineGetter__("event",window_prototype_get_event);
Event.prototype.__defineGetter__("srcElement",event_prototype_get_srcElement);
Event.prototype.__defineGetter__("fromElement", element_prototype_get_fromElement);
Event.prototype.__defineGetter__("toElement", element_prototype_get_toElement);
}

function element_prototype_get_runtimeStyle() { return this.style; }
function window_prototype_get_event() { return SearchEvent(); }
function event_prototype_get_srcElement() { return this.target; }

function element_prototype_get_fromElement() {
var node;
if(this.type == "mouseover") node = this.relatedTarget;
else if (this.type == "mouseout") node = this.target;
if(!node) return;
while (node.nodeType != 1)
node = node.parentNode;
return node;
}

function element_prototype_get_toElement() {
var node;
if(this.type == "mouseout") node = this.relatedTarget;
else if (this.type == "mouseover") node = this.target;
if(!node) return;
while (node.nodeType != 1)
node = node.parentNode;
return node;
}

function SearchEvent()
{
if(document.all) return window.event;
func = SearchEvent.caller;
while(func!=null){
var arg0=func.arguments[0];

if(arg0 instanceof Event) {
return arg0;
}
func=func.caller;
}
return null;
}