title: Alert window when making an ajax call
body: <p>I make an ajax call to a servlet's post method from my js file. 
  I wish to show an alert box till I get a response back. 
  How can i do it using ajax. </p>
  
  <p>The alert window should close after I get response automatically.
  ajax post request</p>
  
  <pre><code>    $.post(fullpath, function(data) {
          fnBookTicket(data);
      });
  </code></pre>