title: What's jQuery's css syntax for addition and subtraction on numerical values?
body: <p>I'm certain I've seen this before. This is how i remember it</p>
  
  <p><code>$cnta.css({ top:'+=50' });</code></p>
  
  <p>Needless to say, it doesn't work :-)</p>
  
  <p>I know i can parse the css value, manipulate the result and put it back into css, but that takes twice the code.</p>
  
  <hr>
  
  <p><strong>Thanks for answers!</strong></p>