css 文本域textarea显示成label标签

 <html>
 <head>
     <title>textarea显示为label</title>
 <style type="text/css">
 .textdisplay {
    background-color:#eeeeee;
    border-bottom-style:none;
    border-left-style:none;
    border-right-style:none;
    border-top-style:none;
    font-size:14px;
 }
 </style>
 <script language="javascript">
 function setTxt(obj){
     if(obj=='e'){
       document.getElementById('sendcontent').className='';
       document.getElementById('sendcontent').readOnly=false;
       document.getElementById('save').disabled=false;
       document.getElementById('cancel').disabled=false;
     }
     if(obj=='c'){
           document.getElementById('sendcontent').className='textdisplay';
           document.getElementById('sendcontent').readOnly=true;
           document.getElementById('save').disabled=true;
           document.getElementById('cancel').disabled=true;
         }
 }
   
 </script>
 </head>
   
 <body>
   
 <textarea class="textdisplay" cols="" rows="" id="sendcontent" name="sendcontent" style="height:500px;width:600px;" readonly>
  <input type="submit" disabled=true id="save" name="save" value="保存" style="height:24px;vertical-align:middle;line-height:20px;" />
 <input type="button" name="edit" value="编辑" style="height:24px; vertical-align:middle;line-height:20px;" onclick="setTxt('e')" />
 <input type="button" disabled=true id="cancel" name="cancel" value="取消" style="height:24px; vertical-align:middle;line-height:20px;" onclick="setTxt('c')" />
 </body>
 </html>