title: Javascript/Jasmine: ReferenceError: Can't find variable: Float64Array
body: <p>I'm using rails, pretty new to javascript and setting up my testframework to test my javascripts with <code>Jasmine</code>.
  Here's the situation:</p>
  
  <p><ul>
  <li>I'm using <code>Viz.js</code> in my source, which is <code>Graphviz</code> compiled to JS with <code>Emscripten</code></li>
  <li>I'm using <code>jasmine-rails</code></li>
  <li><code>jasmine</code> successfully builds from the browser</li>
  <li>however, <code>jasmine:headless</code> (which uses Qt webdriver (Im using Qt version 4.8.1)), gives the following error:</p>
  
  <blockquote>
    <p><code>ReferenceError: Can't find variable: Float64Array</code></li>
    </ul>
    which is coming from Viz.js</p>
  </blockquote>
  
  <p>So my question: can I conclude there are errors in Qt's <code>Float64Array</code>? Has emscripten done a messy job?
  Is there a workaround?</p>