title: jQuery check when PDF download is complete
body: <p>I have a link which when clicked downloads a pdf file.  </p>
  
  <p>Is there a way using jQuery to tell when this has occurred.  Basically I want the link to change from download to please wait.  And when the download is complete it will change to something else.</p>
  
  <p>The main reason is the pdf is generated server side and can take 10 or 20 seconds.</p>