title: double actuating onblur event
body: <p>I have javascript code, which should be executed once at focus shift. Everything works, but this code is carried out two times for some strange reason, thus I give TWO alert windows.</p>
  
  <pre><code>$(document).ready(function() {
      $('#username').blur(function() {
  
          var formData = {
              "username":$('#username').val()
          };
  
          $.ajax({
              url:'check.php',
              type:'POST',
              data:'jsonData=' + $.toJSON(formData),
              success: function(res) {
                  alert(res);
              }
  
          });
      });
  });
  </code></pre>
  
  <p>What am I doing wrong?</p>