title: Submitting a form to a Rails server from jQuery using AJAX isn't working in IE11
body: <p>I'm trying to upload some data from a from to a Rails server using AJAX. The form contains two text inputs and one file input. Here's what my <code>submit</code> event handler looks like:</p>
  
  <pre><code>$("form").on("submit", function(event) {
  
    event.preventDefault();
  
    $.ajax({
      url: $(this).attr("action"),
      type: $(this).attr("method"),
      data: new FormData(this),
      contentType: false,
      processData: false
    });
  });
  </code></pre>
  
  <p>This works fine in every browser except IE. When I try to submit the form in IE, my Rails server spits out the following error:</p>
  
  <pre><code>Unexpected error while processing request: bad content body
          /Users/landonschropp/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rack-1.5.2/lib/rack/multipart/parser.rb:117:in `get_current_head_and_filename_and_content_type_and_name_and_body'
          /Users/landonschropp/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rack-1.5.2/lib/rack/multipart/parser.rb:19:in `block in parse'
          /Users/landonschropp/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rack-1.5.2/lib/rack/multipart/parser.rb:17:in `loop'
          /Users/landonschropp/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rack-1.5.2/lib/rack/multipart/parser.rb:17:in `parse'
          /Users/landonschropp/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rack-1.5.2/lib/rack/multipart.rb:25:in `parse_multipart'
          /Users/landonschropp/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rack-1.5.2/lib/rack/request.rb:377:in `parse_multipart'
          /Users/landonschropp/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rack-1.5.2/lib/rack/request.rb:203:in `POST'
          /Users/landonschropp/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rack-1.5.2/lib/rack/methodoverride.rb:26:in `method_override'
          /Users/landonschropp/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/rack-1.5.2/lib/rack/methodoverride.rb:14:in `call'
          ...
  </code></pre>
  
  <p>I'd appreciate any insights into why this might not be working.</p>