code: function edgeCheck(offset){
  			if(edgeClass){
  				var box         = el.getBoundingClientRect();
  				var windowEdge  = window.innerHeight;
  				
  				// If the bottom-edge is visible (or about to be), enable height animation
  				if(box.bottom + (offset || 0) < windowEdge)
  					elClasses.add(edgeClass)
  				
  				// If the bottom-edge isn't visible anyway, disable height animation immediately
  				else if(box.bottom > windowEdge)
  					elClasses.remove(edgeClass);
  			}
  		}
docs: Internal method to check if an accordion's bottom-edge is visible to the user (or about to be).
  
  @param {Number} offset
  @private