how to return the value back to the previous aspx file when 2 file is parallel running
<p>I have an scenario where I have two aspx pages. When I'm running the first one and I click on a button, that button calls the another one.</p>

<p>So currently that are two aspx files running at the same time, how can I get the second aspx file value in order to fill a TextField on the first one? , my program pass value flow should be like this file1 >> file2 >> file1 (all running at the same time )</p>

<p>1) first file already the session["testing"],</p>

<pre><code>protected void ImageButton1_Click(object sender, ImageClickEventArgs e)
    {

        ClientScript.RegisterStartupScript(this.GetType(), "newWindow", String.Format("&lt;script&gt;window.open('{0}');&lt;/script&gt;", "calendar1.aspx"));
        if(Session["testing"]!=null)
         TextBox1.text = Session["testing"].toString();


    }
</code></pre>

<p>2)after that, the second aspx is running, at the same time the first aspx is concurrently running also, a simple example let say the second file have a value in page_load</p>

<pre><code>protected void Page_Load(object sender, EventArgs e)
    {
        Session["testing"] = "31/12/2012";
    }
</code></pre>

<p>3)but the problem happen here, the first file cannot get the new Session value (immediately) from file2, since that file1 does not re-compile</p>

<pre><code>protected void ImageButton1_Click(object sender, ImageClickEventArgs e)
    {

        ClientScript.RegisterStartupScript(this.GetType(), "newWindow", String.Format("&lt;script&gt;window.open('{0}');&lt;/script&gt;", "calendar1.aspx"));
        if(Session["testing"]!=null)
         TextBox1.text = Session["testing"].toString();


    }
</code></pre>

<p>but it work fine when i click the button second time, it get the Session from file2 created, how can i get the value immediately without click the second time?</p>
