title: python's webbrowser launches IE, instead of default browser, on Windows relative path
body: <p>I'm attempting to launch a local html file from python in the default browser (right now my default is Google Chrome if I double-click on a .html file, Chrome launches.)</p>
  <p>When I use python's <code>webbrowser.open()</code>, IE launches instead, with a blank address bar.</p>
  <pre><code>Python 2.7.1 (r271:86832, Nov 27 2010, 17:19:03) [MSC v.1500 64 bit (AMD64)] on win32
  Type &quot;help&quot;, &quot;copyright&quot;, &quot;credits&quot; or &quot;license&quot; for more information.
  &gt;&gt;&gt; import webbrowser
  &gt;&gt;&gt; filename = 'test.html'
  &gt;&gt;&gt; webbrowser.open('file://'+filename)
  True
  &gt;&gt;&gt; print(webbrowser.get().__class__.__name__)
  WindowsDefault
  </code></pre>
  <p>I've checked my default programs and they look correct.  I'm on Win 7 SP1.  Why is Chrome not launching?</p>
  <p><strong>Update</strong>: The code will be running on unknown OS's and machines, so hardcoding or registering browsers or path updates are not options.  I'm thinking that parsing the url for <code>file://</code> and then doing an <code>os.path.exists</code> check and <code>os.path.realpath</code> might be the answer.</p>