code: function boxTrigger( triggerSetup ) {
  		this.upper = triggerSetup[ 0 ];
  		this.lower = triggerSetup[ 1 ];
  		this.set.apply( this, triggerSetup.slice( 2 ) );
  	}
docs: boxTrigger is an abstract type which describes the relationship between elements that may result in showing the box.  The following type is used by numerous methods to share information about the hypothetical box placement and look by referring to boxTrigger properties.