ASP.NET session in Javascript

Question

I have the following code invoked from a button click - js event

function onOkReason() {
     alert("called");
     var session = $('<%=Session["A"]%>');
     if (session == null) {
         <%Session["A"]%> = "1";
         alert("1");
     }
     else {
         <%Session["A"]%> = null;
         alert("2");
     }

     alert(session);

 }

It does not seem to work...Any pointers as to what may be wrong...

Answer 1

The <% %> is evaluated when the page is processed on the server, you can't then set it from the client - it's to late, the page has been processed and sent back to the clients browser.

You'll need to post back to the server (either full or an AJAX call) to set the data.