層的顯示與隐藏

定義JavaScript方法：

<script language="JavaScript" type="text/JavaScript">

<!--

function MM_findObj(n, d) { //v4.01

  var p,i,x;  if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {

    d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}

  if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];

  for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);

  if(!x && d.getElementById) x=d.getElementById(n); return x;

}

function MM_showHideLayers() { //v6.0

  var i,p,v,obj,args=MM_showHideLayers.arguments;

  for (i=0; i<(args.length-2); i+=3) if ((obj=MM_findObj(args[i]))!=null) { v=args[i+2];

    if (obj.style) { obj=obj.style; v=(v=='show')?'visible':(v=='hide')?'hidden':v; }

    obj.visibility=v; }

}

//-->

</script>

定義一個層：

<div id="Layer1" style="position:absolute; left:14px; top:31px; width:64px; height:61px; z-index:1; visibility:hidden;">

  aaa<br>

  bbb<br>

  ccc<br>

  ddd

</div>

定義出發事件：

<a onMouseOver="MM_showHideLayers('Layer1','','show');" onMouseOut="MM_showHideLayers('Layer1','','hide')">下拉菜單</a>