in javascript Pass variable value in a url

<script type="text/javascript">
d = new dTree('d');
d.add(1,0,'Open The Link','http://111.111.111.111/xyz?prefix=<%=session.getAttribute("Prefix")%>','','_blank');
document.write(d);
</script>


i want to send the session value in the url. How this can be achieved.

What's wrong with that code?

It uses obsolete Java scriptlet expressions for one. Other than that, I guess we'll need to wait for the OP to provide more details.