加引号
'hidden'
'visible'

解决方案 »

  1.   

    <script language=javascript>
    <!--
      function huan(ceng) {
       if(ceng==1)
       {layer1.style.visibility='hidden';
        layer2.style.visibility='visible';
       }
       else
       {layer2.style.visibility='hidden';
        layer1.style.visibility='visible';
       }
      }
    -->
    </script>
    <body>
    ...
    <a onMouseOver="javascript:huan(1)">
    <img src="shuzi_yingwen_2.jpg" width="72" height="30"></a>
    <img src="zhongjian_2.jpg" width="11" height="30">
    <a onMouseOver="javascript:huan(2)">
    <img src="zhongwen_2.jpg" width="74" height="30"></a>
    ...
    </body><div ID=layer1>1</div>
    <div ID=layer2>2</div>
      

  2.   

    用一個等於號且加引號:
    document.layer1.style.visibility='hidden';
    document.layer2.style.visibility='visible';