title: Prevent ajax call from firing twice
body: <p>I have an ajax call</p>
  
  <pre><code>$('#button1').on('click', function(e){
      $.ajax({
        url:  url,
        type: 'POST',
        async: true,
        dataType: 'json',
        enctype: 'multipart/form-data',
        cache: false,
        success: function(data){
  
        },
        error: function(){}
      });
      e.stopImmediatePropagation();
      return false;
  });
  </code></pre>
  
  <p>Now here the response is received after 10 minutes . So the ajax call is called multiple times. Why does this happen / how can we ensure that ajax call is called only once?</p>