title: jQuery IE9-10: unable to get property replace of undefined or null reference
body: <p>I'm developing a page with the following libraries;</p>
  
  <ul>
  <li>jQuery (1.7.2) (older version because of a dependency issue, but have tried up to 1.9.1, doesn't fix issue).</li>
  <li>Backbone (1.1.0)</li>
  <li>lodash (2.4.1)</li>
  <li>modernizr (2.7.1)</li>
  <li>gsap (1.17.0)</li>
  </ul>
  
  <p>The page use canvas and gsap for animation. Everything works great in IE11, Chrome, Safari, Firefox, and IE8 (animations disabled for IE8), but IE9 and 10 just throw this error in the console over and </p>
  
  <blockquote>
    <p>unable to get property 'replace' of undefined or null reference</p>
  </blockquote>
  
  <p>The line referenced is in <code>jquery.js</code>, line 622, which is the return statement in this code:</p>
  
  <pre><code>// Convert dashed to camelCase; used by the css and data modules
  // Microsoft forgot to hump their vendor prefix (#9572)
  camelCase: function( string ) {
      return string.replace( rmsPrefix, "ms-" ).replace( rdashAlpha, fcamelCase );
  },
  </code></pre>
  
  <p>I can't figure out how to determine what part of MY code caused this jQuery code to fire, so I'm unsure as to what may be the issue on my end.</p>
  
  <p>Does anyone know a fix for this? Or alternatively, how I can view what part of my code caused this jquery code to fire (using IE dev tools)?</p>