title: same $.ajax call is ASYNC in Chrome but SYNC in IE
body: <p>I have a dumb simple ajax call to a nonexistent url with an error callback:</p>
  
  <pre><code>$.ajax("non-nonexistent-url", {
      error: function () {
          alert("FOO");
      }
  });
  alert("BAR");
  </code></pre>
  
  <p>When I run it in Chrome, I get "BAR" then "FOO" alerts, which is the behavior I expect - ajax call is asynchronous.
  In IE, however, I get "FOO" then "BAR", which looks like synchronous call, but why? It should be async by default, right?
  I hoped it's guaranteed that <code>$.ajax</code> returns before any callbacks are executed...</p>