title: Ajax.ActionLink not working, Response.IsAjaxRequest() is always false
body: <p>I have been googling/SO:ing this issue for a while and many seem to be sharing this, but I haven't found any successful solution to my problem.</p>
  
  <p>Using MVC3 and Razor.</p>
  
  <ol>
  <li><p>Master page contains:</p>
  
  <p><code>&lt;script src="@Url.Content("~/Scripts/jquery-1.5.min.js")" type="text/javascript"&gt;&lt;/script&gt;</code></p>
  
  <p><code>&lt;script src="@Url.Content("~/Scripts/MicrosoftAjax.js")" type="text/javascript"&gt;&lt;/script&gt;</code></p>
  
  <p><code>&lt;script src="@Url.Content("~/Scripts/MicrosoftMvcAjax.js")" type="text/javascript"&gt;&lt;/script&gt;</code></p></li>
  <li><p>AjaxTest.cshtml contains:</p>
  
  <p><code>&lt;div id="AjaxTestDiv"&gt;content&lt;/div&gt;</code></p>
  
  <p><code>@Ajax.ActionLink("Update", "AjaxTester", new AjaxOptions { UpdateTargetId = "AjaxTestDiv" })</code></p></li>
  <li><p>AjaxTester action method:</p>
  
  <pre><code>public string AjaxTester()
  {
      if (Request.IsAjaxRequest())
      {
          return DateTime.Now.ToString();
      }
      else
      {
          return "FAIL";
      }
  }
  </code></pre></li>
  </ol>
  
  <p>I always get the "FAIL" returned, to a blank page, not in the targeted div.</p>
  
  <p>Edit: Also note that if I remove the if (Request.IsAjaxRequest()), I still don't get back anything to the targeted div, but instead a  blank page.</p>
  
  <p>Edit2: Looking at the HTML generated, this is my link:</p>
  
  <pre><code>&lt;a data-ajax="true" data-ajax-method="POST" data-ajax-mode="replace"
  data-ajax-update="#AjaxTestDiv" href="/Area/AjaxTester"&gt;Update&lt;/a&gt;
  </code></pre>
  
  <p>Have tried switching the method to GET, to no avail.</p>