title: Bootstrap: modal over modal
body: <p>I was trying to find a simple function that would overlay modals on each other, so that one modal could trigger a second one.
  That means that the modals have to be one over the other using the z-index and therefore we need to do the same to the backdrop (the translucent overlay).</p>
  
  <p>I found a few plugins, some answers using pure css etc.
  Here's mine in case it can help you, you don't have to add anything but these few lines !</p>