Answer by Justin Niessner for What is the reason for var $this = this

In this case, nothing. $this is just another variable declaration which has this assigned to it.

Typically, I've seen this shortcut used by people using JavaScript libraries when wrapping this. For example, typical usage in jQuery would be:

// rather than writing $(this) everywherevar $this = $(this);$this.each(function(){    // Do Something});