title: Display a spinner while sending a sync Ajax request
body: <p>I need to display a spinner while sending a synchronous Ajax request to the server to retrieve data.</p>
  
  <p>I know it is better to do it in asynchronous mode but I'm not allow to do it.
  I also know sync ajax request blocks the browser.</p>
  
  <p>I already found a solution with a setTimeout to delay the call of my ajax request but my boss doesn't want me to use setTimeout.</p>
  
  <p>Do you have any solution to solve my problem please ? Thank you very much !</p>