Passing a javascript variable to JSP

Hi.

I'm trying to get a String value from my Javascript form and place it in a session attribute, so I can later get it via JSP code.

I tried this: I created a hidden form field in my form called "mainForm", in my JSP page called "mainPage.jsp":

<FORM name="mainForm" onsubmit="mainPage.jsp"> <input type="hidden" name="unseenBox"> ...

then I placed a button later on:

<INPUT type="button" value="Magic Button" onClick="passToJSP()">

Btw, the form has a bunch of events which make sure that the variable called "myString" is filled up appropriately. I checked this with an alert button and myString is definitely set correctly.

I then created a function which cunningly submitted a form to the same page, which was supposed to place this string in a request parameter supposedly allowing my JSP code to grab it and place it in a session attribute:

function passToJSP() { document.mainForm.unseenBox.value=myString; setTimeout('document.mainForm.submit()',500); <% session.setAttribute("myString", request.getParameter("myString")); %> top.location.reload(); }

This function reloads all the frames, and I was hoping another frame could know freely access myString and use it in its own JSP code. Unfortunately this session attribute never gets set to anything other then null.

What am I doing wrong? And is there a more elegant solution to this trivial issue?

Thanks in advance. Cheers!

JSP and JSTL has executed long before the HTML page gets sent to the browser.

You have a fundamental misconception of how JSP operates. Please read this article to find out why what you are doing can't work and how JSP operates.