title: when select image that wide != 500 px., why ie7 not show aleart message?
body: <p>.....................................................................................................................................................................</p>
  
  <p>when select image that wide != 500 px., why ie7 not show aleart message ?</p>
  
  <p>.....................................................................................................................................................................</p>
  
  <pre><code>&lt;script src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"&gt;&lt;/script&gt;
  
  &lt;input name="offer_image_1" type="file" id="offer_image_1" /&gt;
  
  &lt;script type="text/javascript"&gt;
  var _URL = window.URL || window.webkitURL;   // for check wide and height image
  $("#offer_image_1").change(function(e) {
      var offer_image_1, img;
      if ((offer_image_1 = this.files[0])) {
          img = new Image();
          img.onload = function() {
              if (this.width != '500')
              {
              alert("not width 500 px.");
              }
          };
          img.src = _URL.createObjectURL(offer_image_1);
      }
  });
  &lt;/script&gt;
  </code></pre>