title: Can't change Content Type header of fileDownload.js jQuery plugin
body: <p>I am using the jQuery plugin called <a href="https://github.com/johnculviner/jquery.fileDownload" rel="nofollow">fileDownload.js</a> </p>
  
  <p>I cannot seem to change the <code>Content-Type</code> header to anything at all.
  The default is <code>x-www-form-urlencoded</code>.</p>
  
  <p>On my express server that is the only header I have been able to get from fileDownload.js</p>
  
  <p>Here is what my code looks like.</p>
  
  <pre><code>$.fileDownload(url, {
      httpMethod:'POST',
      'Content-Type': 'application/json; charset=utf-8',
      data: inputData,
      dataType: 'json',
      successCallback: function() {},
      failCallback: function() {}
  });
  </code></pre>
  
  <p>Any ideas why I can't get any content type besides the default <code>x-www-form-urlencoded</code>?</p>