This is a short simple quick tip, I re-use a lot of my code, ( it's called going green ) anyway sometimes I forget to remove some common jQuery plug-in call's that I use a lot like Lightboxes, Choosen Selects, jEditable, etc, etc. So I find just adding a quick check to make sure the method exists before calling it is very helpful.

One way of checking if a method exists is like this

  if (typeof $.fn.pluginname != 'undefined')

Or the short-hand version

  if($.fn.pluginname)

Just replace "pluginname" with whatever your calling like below

  if($.fn.pluginname)

    // Verify there is a method named "chosen", then verify we need to use it.
    if ($(".chzn-select").length > 0 && typeof $.fn.chosen !== 'undefined')
    {
        $(".chzn-select").chosen();
    }