title: Jquery: change input file value inside an iframe
body: <p>I have a page where there is an input file. In this page there also is an iframe that contains another input file.</p>
  
  <p>So, when the input file in main page changes, I want that the input file inside iframe also changes its value to the value of external input file.</p>
  
  <p>But it doesn't work, i use this code in main page:</p>
  
  <pre><code>$('#iframe').contents().find('#input_file').val(myvalue);
  </code></pre>
  
  <p>The value of <code>#input_file</code> file remains empty.  What could be the problem</p>