title: jQuery $.ajax post variables inside request header
body: <p>I am making request calls using $.ajax, with post.</p>
  
  <p>The problem is, the post variables are becoming part of the request header, which is causing error when our software is using it to check signatures using the request.</p>
  
  <pre><code>$.ajax({
      url: oauth.signed_url,
      type: "POST",
      beforeSend: function(jqXHR, settings) {},
      dataType: "json",
      headers: oauth.header,
      data: {
          description: "TESTME2222"
      },
      success: function(data) {
          //console.log(data);
      }
  });
  </code></pre>
  
  <p>This line: <code>headers: oauth.header,</code> is the header I want to use, but apparently it appends to the existing header. Is there any way to replace headers?</p>
  
  <p>EDIT:</p>
  
  <p>I understand I can modify the headers using beforeSend function, but the problem is, i want to get rid of some of them. From what I know, can't really do that using the jqXHR object. It would be easier for me if i just replace the whole thing.</p>