the code below run correctly in IE, but the float menu didn't display in
mozilla explorer, what is the trouble?
menu.htm:

<script language="javascript">
document.writeln("     <DIV id=menuDiv style=\"Z-INDEX: 2; VISIBILITY:
hidden; WIDTH: 50px; POSITION: absolute; HEIGHT: 1px; BACKGROUND-COLOR:
#ffffff\"></DIV>");

//????????????????
var h;
var w;
var l;
var t;
var topMar = 1;
var leftMar = -2;
var space = 1;
var isvisible;
var MENU_SHADOW_COLOR='#ffffff';//??????????????????
var global = window.document
global.fo_currentMenu = null
global.fo_shadows = new Array

function HideMenu()
{
var mX;
var mY;
var vDiv;
var mDiv;
if (isvisible == true)
{
 vDiv = document.all("menuDiv");
 mX = window.event.clientX + document.body.scrollLeft;
 mY = window.event.clientY + document.body.scrollTop;
 if ((mX < parseInt(vDiv.style.left)) || (mX >
parseInt(vDiv.style.left)+vDiv.offsetWidth) || (mY <
parseInt(vDiv.style.top)-h) || (mY >
parseInt(vDiv.style.top)+vDiv.offsetHeight)){
  vDiv.style.visibility = "hidden";
  isvisible = false;
 }
}
}

function ShowMenu(vMnuCode,tWidth) {
     var e  = window.event ;
  var vSrc = e.target || e.srcElement;
//  var vSrc=e.target?e.target:e.srcElement;

 vMnuCode = "<table border=0 id='menu' cellspacing=1 cellpadding=3
style='width:"+tWidth+"' class=MenuDropDown onmouseout='HideMenu()'><tr
height=23><td nowrap align=left class=MenuDropDown>" + vMnuCode +
"</td></tr></table>";

h = vSrc.offsetHeight;
w = vSrc.offsetWidth;
l = vSrc.offsetLeft + leftMar+4;
t = vSrc.offsetTop + topMar + h + space-2;

vParent = vSrc.offsetParent;

while (vParent.tagName.toUpperCase() != "BODY")
{

 l += vParent.offsetLeft;
 t += vParent.offsetTop;
 vParent = vParent.offsetParent;
}

menuDiv.innerHTML = vMnuCode;
menuDiv.style.top = t;
menuDiv.style.left = l;
menuDiv.style.visibility = "visible";
isvisible = true;

}

s4='<a href=#>open</a><br>';
s4+=' <a href=#> save</a> <br>';
s4+='<a href=#>close</a><br>';
s4+='<a href=#>close all</a><br>';
s4+='<a href=#>exit</a><br>';

</script>
<table>
 <tr>
 <td>
 <a href="#"
 onmouseover ="javascript:ShowMenu(s4,80)"
 onmouseout="HideMenu()" > File
 </a></td>
</tr></table