Passing javascript variable to XSL

Hi,
I have a requirement where i need to pass the javascript variable to XSL which actually calls a java method(the javascript var is parameter to this method)
Eg:
function xx(a) {
var x =Value selected from the dropdown box (a here)
<xsl:variable name="aa" select="xx:javamethod(javascript var x): />

if i simple pass x to the method,the value in x is not passed instead the value X itself is passed
Pls help me how to achieve this..
Thanks in advance

Not possible as XSL is executed first to transform XML into HTML document that may contain Javascript. Just submit the page and call the java method passing the selected item.