title: Javascript : What does contentType: !1 means?
body: <p>I have seen in multiple cases where the   <code>contentType</code>,    <code>cache</code>    etc are mentioned as <code>!1</code>. Haven't seen much documentation for the same. Can someone tell me what that means?</p>
  <pre><code>$.ajax({
                   url: url,
                   data: FormData1,
                   cache: !1,
                   contentType: !1,
                   processData: !1,
                   type: 'POST',
                   beforeSend: function() {},
                   complete: function(responseData){
      
                  }
                });
  </code></pre>