メニューのリンクに触れると、背景色が変わります。 
<HTML>
<HEAD>
<TITLE>Change background color onlayer</TITLE>
<SCRIPT TYPE="text/javascript">
<!--
function changeBGC(targetID,textbgc){
  if(document.all){
    document.all(targetID).style.backgroundColor = textbgc;
    }
  if(document.layers){
    document.layers[targetID].bgColor=textbgc;
  }
}
// -->
</SCRIPT>
</HEAD>
<BODY>
<DIV ID="menu1" style="position: absolute; left: 8px; top: 16px; width: 140px; height: z-index: 1"><A HREF="#" onMouseover="changeBGC('menu1','#FFCCFF')" onMouseout="changeBGC('menu1','#FFFFFF')">*MENU1</A></DIV>
<DIV ID="menu2" style="position: absolute; left: 8px; top: 36px; width: 140px; height: z-index: 2"><A HREF="#" onMouseover="changeBGC('menu2','#FFFFCC')" onMouseout="changeBGC('menu2','#FFFFFF')">*MENU2</A></DIV>
<DIV ID="menu3" style="position: absolute; left: 8px; top: 56px; width: 140px; height: z-index: 3"><A HREF="#" onMouseover="changeBGC('menu3','#CCFFFF')" onMouseout="changeBGC('menu3','#FFFFFF')">*MENU3</A></DIV>
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