请问怎样修改以下的javascript?

<html><head>
<script language="JavaScript1.2">
var crossobj;
function initializedrag(e)
{
  crossobj=document.all? document.getElementById("showimage") : document.all;
}document.onmousedown=initializedrag;function showbox(bShow)
{
 crossobj.style.visibility= bShow? "visible" : "hidden";
}
</script>
<div id="showimage"  style="position:absolute;width:250px;left:500;top:250;visibility:hidden">
<table border="0" width="250" bgcolor="#000080" cellspacing="0" cellpadding="2">
  <tr>
    <td width="100%"><table border="0" width="100%" cellspacing="0" cellpadding="0"
    height="36">
      <tr>
        <td  width="100%"></td>
        <td style="cursor:hand"><a href="#" onClick="showbox(false);return false"><img src="close.gif" 
width="16"  height="14" border=0></a></td>
      </tr>
      <tr>
        <td width="100%" bgcolor="#FFFFFF" style="padding:4px" colspan="2">
         Testing 1 2 3
         </td>
      </tr>
    </table>
    </td>
  </tr>
</table>
</div>
<a href="#" onclick="showbox(true);return false">popout</a>
</body></html>