How to get parameter from URL - part II

Question

Is there a way to assign a value of JavaScript variable to JSF variable?, something like
<h:commandButton value="Send" actionListener ="#{myBean.myAction}" 
<f:attribute name="source" value="<some JavaScript variable>"/>
</h:commandButton>Here is my problem
Following the thread in http://forum.java.sun.com/thread.jspa?forumID=427&threadID=545973
I have a facelets page that is used as a "contact us" from this page the information is send to the action bean for saving in the database. We want to know where the users come from to this page. This can be done either by using the "referring page" or adding parameters to the URL - http://mylink?param=myval
In both cases the problem is that when transferring the information from the faclets page to the action bean the information is lost and instead of showing the "real" referring page or parameter it shows the information of the faclets page.
One solution to the problem is to save the information in the faclets page in a javascript variable and then transfer it using the f:attribute to the action bean. By the way, the opposing is very easy, one can save easy the value of a JSF parameter in a javascript variable:
<script type="text/javascript">
     // <![CDATA[
     var foo = "#{myBean.bar}"
// ]]>
</script>

Answer 1

I can, but the EL doesn't contain the "right" value..
But there is a general question
Can one use javascript in expression like f:attribute ?
BTW I solved the above problem by using AJAX like behavior, But I wanted to know if there is another way