title: use html and javascript for file selection dialog in jupyter notebook
body: <p>In a jupyter notebook I'd like to use html/javascipt for a file selection dialog instead of tkinter.  After some messing around I was able to get this to work and even make the result available to the python kernel.  BUT, now I think I see why no one else does this... javascript is not aware of the full path to these files.</p>
  
  <p>I was quite proud of this (inside of a jupyter cell):</p>
  
  <pre class="lang-html prettyprint-override"><code>%%html
  &lt;input type="file" accept=".dat" id="files" name="files[]" multiple /&gt;
  &lt;output id="list"&gt;&lt;/output&gt;
  
  &lt;script&gt;
      function handleFileSelect(evt) {
          var files = evt.target.files;
          var output = [];
          IPython.notebook.kernel.execute("lstFiles=[]");
          for (var i = 0, f; f = files[i]; i++) {
              IPython.notebook.kernel.execute("lstFiles.append('" + f.name + "')");
              output.push('&lt;li&gt;&lt;strong&gt;', f.name, '&lt;/strong&gt;&lt;/li&gt;');
          }
          document.getElementById('list').innerHTML = '&lt;ul&gt;' + output.join('') + '&lt;/ul&gt;';
      }
  
      document.getElementById('files').addEventListener('change', handleFileSelect, false);
  &lt;/script&gt;
  </code></pre>
  
  <p>then in another cell...</p>
  
  <pre class="lang-py prettyprint-override"><code>print(lstFiles)
  </code></pre>
  
  <p>This gets me the list of files, but not the path.  Is there any trick to getting the path?  Or even the browser's last used location?</p>