javascript code compatible with FF's onmouseenter and onmouseleave_javascript skills

There are onmouseenter and onmouseleave under IE to solve this problem.
It’s a pity that ff doesn’t have it. I thought again, why is such a good function not quoted by ff?
There is also onpropertychange in ie, but it doesn’t exist in ff. . .

A piece of js is introduced in the comparison example to be compatible with FF's onmouseenter and onmouseleave.:

Copy code Code As follows:

var xb =
{
    evtHash: [],

    ieGetUniqueID: function(_elem)
    {
        if (_elem === window) { return 'theWindow'; }
        else if (_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); }
            else if (_evtName == 'mouseleave')
                { _elem.addEventListener('mouseout', xb.mouseEnter(_fn), _useCapture); } 
            else
                { _elem.addEventListener(_evtName, _fn, _useCapture); }
        }
        else if (typeof _elem.attachEvent != 'undefined')
        {
            var key = '{FNKEY::obj_'   xb.ieGetUniqueID(_elem)   '::evt_'   _evtName   '::fn_'   _fn   '}';
            var f = xb.evtHash[key];
            if (typeof f != 'undefined')
                { return; }

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

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

            // attach unload event to the window to clean up possibly IE memory leaks
            window.attachEvent('onunload', function()
            {
                _elem.detachEvent('on'   _evtName, f);
            });

            key = null;
            //f = null;   /* DON'T null this out, or we won't be able to detach it */
        }
        else
            { _elem['on'   _evtName] = _fn; }
    },    

    removeEvent: function(_elem, _evtName, _fn, _useCapture)
    {
        if (typeof _elem.removeEventListener != 'undefined')
            { _elem.removeEventListener(_evtName, _fn, _useCapture); }
        else if (typeof _elem.detachEvent != 'undefined')
        {
            var key = '{FNKEY::obj_'   xb.ieGetUniqueID(_elem)   '::evt'   _evtName   '::fn_'   _fn   '}';
            var f = xb.evtHash[key];
            if (typeof f != 'undefined')
            {
                _elem.detachEvent('on'   _evtName, f);
                delete xb.evtHash[key];
            }

            key = null;
            //f = null;   /* DON'T null this out, or we won't be able to detach it */
        }
    },

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

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

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

        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