php and js concat problem

[neel1979]

<SCRIPT LANGUAGE="JavaScript">
<!--
var ht = 100;
var wt = 100;
//-->
</SCRIPT>
<?php
$txt = "<a href=\"#\" onclick=\"javascript: window.open('". $mitem->link ."', '', 'toolbar=no,location=no,status=no,menubar=no,scrollbars=yes,resizable=yes,width="+wt+",height="+ht+"'); return false\" class=\"$menuclass\" ". $id .">". $mitem->name ."</a>\n";
?>

When I am trying to concat ht and wt, the above code is giving error. What am I doing wrong?

Regards,
Nilanjan