javascript图片渐显效果代码

在<head>到</head>之间插入如下的JAVASCRIPT代码：
<script> nereidFadeObjects = new Object(); nereidFadeTimers = new Object(); function nereidFade(object, destOp, rate, delta){ if (!document.all) return if (object != "[object]"){ setTimeout("nereidFade("+object+","+destOp+","+rate+","+delta+")",0); return; } clearTimeout(nereidFadeTimers[object.sourceIndex]); diff = destOp-object.filters.alpha.opacity; direction = 1; if (object.filters.alpha.opacity > destOp){ direction = -1; } delta=Math.min(direction*diff,delta); object.filters.alpha.opacity+=direction*delta; if (object.filters.alpha.opacity != destOp){ nereidFadeObjects[object.sourceIndex]=object; nereidFadeTimers[object.sourceIndex]=setTimeout("nereidFade(nereidFadeObjects["+object.sourceIndex+"],"+destOp+","+rate+","+delta+")",rate); } } </script> 在要插入的图片添加如下代码： <img onMouseOut=nereidFade(this,50,10,4) onMouseOver=nereidFade(this,100,10,4) style="FILTER: alpha(opacity=50)" src="https://www.jb51.net/www.gxlcms.com/images/logo.gif">
[Ctrl+A 全选 注:如需引入外部Js需刷新才能执行]
*其中onMouseOver=nereidFade(this,50,10,4)中 style="FILTER: alpha(opacity=50)"表示图片的透明度为50%