. . .
div>
mydiv0
<div>mydiv1</div>
<div>mydiv2</div>
<div>mydiv3</div>
<table id="mytable">
<tr>
<td>
 1 
</td>
<td>
 2 
</td>
<td>
 3 
</td>
</tr>
</table>
<div>mydiv4</div>
<div>mydiv5</div>
</div>
. . .


<SCRIPT type=text/javascript>
function wrapWithDIV(ID,wrapperID){
  var el=document.getElementById(ID);
  if(!el){ alert("No element: " + ID);return; }
  var chidNodes=el.parentNode.childNodes;
  for(var n in chidNodes){
    if(chidNodes[n]===el){
      var div=document.createElement('div');
      div.id=wrapperID;
      el.parentNode.replaceChild(div,el);
      div.appendChild(el);
      div.style.border="1px solid #FF0000";
      div.style.padding="1px";
      break;
    }
  }
}
window.onload=function(){
  wrapWithDIV('mytable','block1');
  wrapWithDIV('block1','block2');
  wrapWithDIV('block2','block3');
}
</SCRIPT>
</head>