title: How to display 'Loading' when making a 'synchronous' AJAX call in pure JavaScript?
body: <p>I want to make sure the result is shown to user, so I make synchronous AJAX call. It's quite simple to display a 'Loading' indicator with asynchronous AJAX (the examples are everywhere), but when I use synchronous AJAX call with XMLHttpRequest, the loading indicator GIF image doesn't show up at all.</p>
  
  <p>Some said that it's impossible to show indicator when doing a synchronous call (block until having response from server). But I just want to ask to see whether there's a way to do it.</p>