isOnScreen

isOnScreen

$.fn.isOnScreen = function(shift){
		if(!shift){
			shift = 0;
		}
	  var viewport = {};
	  viewport.top = $(window).scrollTop();
	  viewport.bottom = viewport.top + $(window).height();
	  var bounds = {};
	  bounds.top = this.offset().top + shift;
	  bounds.bottom = bounds.top + this.outerHeight() - shift;
	  return ((bounds.top <= viewport.bottom) && (bounds.bottom >= viewport.top));
};