Width van windows opvragen!

<script language="javascript">
function popup() {
   return;
}

function venster(breedte, hoogte, bron, titel) {
   var links = Math.round(screen.width/2 - breedte/2);
   var boven = Math.round(screen.height/2 - hoogte/2);
   window.open(bron, titel, "width="+breedte+",height="+hoogte+",top="+boven+",left="+links+",scrollbars=no,resizable=no,menubar=no,toolbar=no,status=no");
}
</script>

<a href="popup();" onClick="venster(200,200,'pagina.php', 'test');">Klik</a>

<script language="javascript">
function popup() {
   return;
}
 
function venster(breedte, hoogte, bron, titel) {
   var links = Math.round(screen.width/2 - breedte/2);
   var boven = Math.round(screen.height/2 - hoogte/2);
   window.open(bron, titel, "width="+breedte+",height="+hoogte+",top="+boven+",left="+links+",scrollbars=no,resizable=no,menubar=no,toolbar=no,status=no");
}
</script>
 
<a href="popup();" onClick="venster(200,200,'pagina.php', 'test');">Klik</a>

if (document.documentElement && document.documentElement.clientWidth)
   theWidth = document.documentElement.clientWidth;
else
   theWidth = document.body.clientWidth;

if (document.documentElement && document.documentElement.clientWidth)
   theWidth = document.documentElement.clientWidth;
else
   theWidth = document.body.clientWidth;

<style>
#dropmenudiv{
            <SCRIPT LANGUAGE="JavaScript1.2">
	  var width = document.documentElement.clientWidth
	  document.write("left: "+ width - 100+ ";")
            </SCRIPT>
}

<style>
#dropmenudiv{
            <SCRIPT LANGUAGE="JavaScript1.2">
	  var width = document.documentElement.clientWidth
	  document.write("left: "+ width - 100+ ";")
            </SCRIPT>
}

#dropmenudiv{
	left:100;
}

#dropmenudiv{
	left:100;
}

<script language="JavaScript1.2" text='text/javascript'>
<!--
    var lala 	 = document.getElementById('dropmenudiv');
    var width  = document.documentElement.clientWidth;
    
 /* weer niet zeker of left te definieëren valt in js anders kan je padding oid gebruiken..  */
    lala.style.left = width+100;
--//>
</script>

<script language="JavaScript1.2" text='text/javascript'>
<!--
    var lala 	 = document.getElementById('dropmenudiv');
    var width  = document.documentElement.clientWidth;
 
 /* weer niet zeker of left te definieëren valt in js anders kan je padding oid gebruiken..  */
    lala.style.left = width+100;
--//>
</script>

<script language="JavaScript1.2" text='text/javascript'>
<!--
	sheet.addRule("#dropmenudiv", "background-color: #000000", -1);
--//>
</script>

<script language="JavaScript1.2" text='text/javascript'>
<!--
	sheet.addRule("#dropmenudiv", "background-color: #000000", -1);
--//>
</script>

<style>
#dropmenudiv{
	position:absolute;
	border:1px solid black;
	border-bottom-width: 0;
	font:normal 12px Verdana;
	line-height:18px;
	z-index:200;
	border-bottom: 1px solid black;
	overflow: visible;
	visibility: visible;
}
</style>

<style>
#dropmenudiv{
	position:absolute;
	border:1px solid black;
	border-bottom-width: 0;
	font:normal 12px Verdana;
	line-height:18px;
	z-index:200;
	border-bottom: 1px solid black;
	overflow: visible;
	visibility: visible;
}
</style>

/* definieër de style sheet als volgt: */
<style id="abc" TYPE="text/css">

<script language="JavaScript1.2" text='text/javascript'>
<!--
document.styleSheets["abc"].addRule ("#dropmenudiv", "background-color: #000000");
}
//-->
</script>

/* definieër de style sheet als volgt: */
<style id="abc" TYPE="text/css">
 
<script language="JavaScript1.2" text='text/javascript'>
<!--
document.styleSheets["abc"].addRule ("#dropmenudiv", "background-color: #000000");
}
//-->
</script>