how can i put java script value into jsp variable?

dear sir:
i know how to put jsp value into java script variable
but how to put java script vaule into jsp variable? thanks;

<%
String s="hello",b="";
%>
<script language="javascript">
var name="<%=s%>";
<%b%>=name;<=== is this correct?
</script>

YOu can put JSP value into JavaScript variable, but reverse is not possible.
Your code dont work.

The JSP variables exist when the JSP is being processed on the server. At that point the Javascript variables are just markup. Later, when the output of the JSP is processed on the client, the Javascript variables exist but the JSP variables are long gone.

So you can't do that. I would attempt to answer the real question behind your question but I can't tell what it is.

Please read this article for information on the life-cycle of a JSP and why what you are asking is not possible.