title: "Modernizr is not defined"
body: <p>My app includes Modernizr (concatenated with prefixfree) just before the closing <code>&lt;head&gt;</code> tag, and the rest of the js just before the closing <code>&lt;body&gt;</code> tag. 99.9% of the time this works fine, but sometimes I get <code>Modernizr is not defined</code>.</p>
  
  <p>The code causing the error is:</p>
  
  <pre><code>if(!Modernizr.csscalc) {
    // do stuff
  }
  </code></pre>
  
  <p>This error happens on real clients (I get notifications by email), so I don't have much more data than this error string. I also fail to reproduce it, even on same OS and browser.</p>
  
  <p>I have no clue for what may be the cause of this sporadic error. Could you please direct me? Am I doing something wrong here?</p>