getJSON not work in Chrome

getJSON not work in Chrome

Why  jQuery.getJSON() not work in Chrome 5.0? but work in IE8. This my example:

<!DOCTYPE html>
<html>
<head>
  <script src="http://code.jquery.com/jquery-latest.min.js"></script>
  <script>

$(document).ready(function () {

 $.getJSON("http://exy.com.ua/q/index.php", "",  function(data) { 
 alert ("b = " + data.a);
}
);

});
</script>
</head>
<body>
</body>
</html>