title: An incorrect even gets triggered if the browser back button is clicked
body: <p>Here's my aspx page</p>
  
  <pre><code>&lt;asp:Label runat="server" ID="lbl" Text="suff goes here" /&gt;&lt;br /&gt;
  &lt;asp:Button runat="server" OnClick="btnClick" ID="btn" Text="Click me!" /&gt;
  &lt;asp:DropDownList runat="server" ID="ddl" 
                    OnSelectedIndexChanged="ddlChanged" 
                    AutoPostBack="true"&gt;
      &lt;Items&gt;
          &lt;asp:ListItem&gt;a&lt;/asp:ListItem&gt;
          &lt;asp:ListItem&gt;b&lt;/asp:ListItem&gt;
          &lt;asp:ListItem&gt;c&lt;/asp:ListItem&gt;
      &lt;/Items&gt;
  &lt;/asp:DropDownList&gt;
  </code></pre>
  
  <p>And here's the code behind</p>
  
  <pre><code>protected void btnClick(object sender, EventArgs e)
  {
      lbl.Text = DateTime.Now.Ticks.ToString();
  }
  
  protected void ddlChanged(object sender, EventArgs e)
  {
      Response.Redirect("Page2.aspx");
  }
  </code></pre>
  
  <p>When I click something in the dropdown, I get redirected to Page2, I then click the browser back button, and click the "Click Me!" btn. Instead of the <code>btnClick</code> even getting fired, it fires <code>ddlChanged</code> first, and does the redirect again. </p>
  
  <p>Can this be solved without javascript? </p>