title: jQuery post respond with readyState:0, status:0
body: <p>all. I am using a jquery version 1.6.2.
  I do a ajax call like this:</p>
  
  <pre><code>  var jqxhr = $j.post(myPHP, function() {
            alert("success");
          })
          .success(function() { alert("second success"); })
          .error(function(data) { alert(JSON.stringify(data)); })
          .complete(function() { alert("complete"); });
  </code></pre>
  
  <p>The script, run, and show error, than, complete. Some people may thing that...myPHP have some problem, but the myPHP is always show:</p>
  
  <pre><code>{"sayHi":"hihi"}
  </code></pre>
  
  <p>So, I go to firebugs to check whether the link have any problem, when I called..:
  It show me the POST url with status 200, which is ok. Also, I can see the respond via firebugs....
  But the question is ....why the jquery so me have a error...:
  And here is the error msg:</p>
  
  <pre><code>{"readyState":0,"responseText":"","status":0,"statusText":"error"}
  </code></pre>