title: Disable button with jQuery -- IE9 problem
body: <p>I have a snippet of code that disables upload button until something is selected to be uploaded. I just noticed that it does not work in IE9 Beta. Do I need to iterate it somehow more for IE? Here's my code:</p>
  
  <pre><code>$("input:file").change(function(){
      if ($(this).val()) {
          $("input:submit").attr("disabled",false);
      }
  });
  </code></pre>
  
  <p>UPDATE:</p>
  
  <p>I modified my code to add an alert:</p>
  
  <pre><code>$("input:file").change(function(){
      alert("...");
      if ($(this).val()) {
          $("input:submit").removeAttr("disabled");
      }
  });
  </code></pre>
  
  <p>In FF alert comes on and enables button, in IE alert is not triggered.</p>
  
  <p>ONE MORE UPDATE:</p>
  
  <p>The problem went ahead without code modification. In IE9 there's a new icon for "COMPATIBILITY VIEW" next to web address field. I clicked it to enable and then clicked again to disable and the issue went away. My guess, IE blocked jQuery somehow and cached it. By changing the compatibility settings I might've removed cached settings. WEIRD!</p>