title: Prepend an onclick action on a button with JQuery
body: <p>I have a button that already has an onclick-event and an assigned function. I wish to add another function call in front of it. I can imagine it should be possible to fiddle around with the onclick attribute (<code>attr</code>), but I do not think this is best practice.</p>
  
  <p>What would you consider best practice to prepend a function call on an existing onclick-event?</p>