title: ajax start event does not work in async false
body: <p>I create an ajax request with async false. And then I put some text into textbox in global ajax start event. The input text is not filled before ajax request completed in IE and chrome but it is filled in firefox. Please see below.</p>
  
  <pre><code>&lt;input type="text" id="text1" /&gt;
  &lt;input type="button" id="button1" /&gt;
  &lt;script type="text/javascript"&gt;
         $(document).ajaxStart(function () {
             $("#text1").val("testing");
         });
  
        $("#button1").click(function(){
             $.ajax({
                 type: 'POST',
                 url: '',
                 data: '',
                 async: false,
                 dataType: 'text', 
            });
         });
  &lt;/script&gt;
  </code></pre>
  
  <p>What is a reason for that? How can I solve this?</p>
  
  <p>P.S. It is working well with async true.</p>