IE下有onmouseenter和onmouseleave来解决。
可惜ff就没有。我再想，为什么这么好的功能，为什么ff不引用呢？
还有ie中的onpropertychange，哎，ff中都没有。。。

对比例子中引入了一段js，来兼容FF的onmouseenter和onmouseleave.：
复制代码 代码如下:
varxb=
{
evtHash:[],

ieGetUniqueID:function(_elem)
{
if(_elem===window){return'theWindow';}
elseif(_elem===document){return'theDocument';}
else{return_elem.uniqueID;}
},

addEvent:function(_elem,_evtName,_fn,_useCapture)
{
if(typeof_elem.addEventListener!='undefined')
{
if(_evtName=='mouseenter')
{_elem.addEventListener('mouseover',xb.mouseEnter(_fn),_useCapture);}
elseif(_evtName=='mouseleave')
{_elem.addEventListener('mouseout',xb.mouseEnter(_fn),_useCapture);}
else
{_elem.addEventListener(_evtName,_fn,_useCapture);}
}
elseif(typeof_elem.attachEvent!='undefined')
{
varkey='{FNKEY::obj_'+xb.ieGetUniqueID(_elem)+'::evt_'+_evtName+'::fn_'+_fn+'}';
varf=xb.evtHash[key];
if(typeoff!='undefined')
{return;}

f=function()
{
_fn.call(_elem);
};

xb.evtHash[key]=f;
_elem.attachEvent('on'+_evtName,f);

//attachunloadeventtothewindowtocleanuppossiblyIEmemoryleaks
window.attachEvent('onunload',function()
{
_elem.detachEvent('on'+_evtName,f);
});

key=null;
//f=null;
}
else
{_elem['on'+_evtName]=_fn;}
},

removeEvent:function(_elem,_evtName,_fn,_useCapture)
{
if(typeof_elem.removeEventListener!='undefined')
{_elem.removeEventListener(_evtName,_fn,_useCapture);}
elseif(typeof_elem.detachEvent!='undefined')
{
varkey='{FNKEY::obj_'+xb.ieGetUniqueID(_elem)+'::evt'+_evtName+'::fn_'+_fn+'}';
varf=xb.evtHash[key];
if(typeoff!='undefined')
{
_elem.detachEvent('on'+_evtName,f);
deletexb.evtHash[key];
}

key=null;
//f=null;
}
},

mouseEnter:function(_pFn)
{
returnfunction(_evt)
{
varrelTarget=_evt.relatedTarget;
if(this==relTarget||xb.isAChildOf(this,relTarget))
{return;}

_pFn.call(this,_evt);
}
},

isAChildOf:function(_parent,_child)
{
if(_parent==_child){returnfalse};

while(_child&&_child!=_parent)
{_child=_child.parentNode;}

return_child==_parent;
}
};
本篇文章来源于cssrain.cn原文链接：http://www.cssrain.cn/article.asp?id=952