jQuery plugin to stick element when scrolling

stickme.js

  $.fn.stickMe = function(options) {
     return this.each(function() {
        var $this = $(this);
        function onScroll() {

          var topToElementStart = $this.offset().top - (options.startOffset + options.offset);
          var topToViewportTop = $(window).scrollTop();
          var topToViewportBottom = $(window).scrollTop() + $(window).height();
          var topToElementEnd = $this.offset().top + options.height;

          if( topToViewportTop > topToElementStart ) {
            if (topToViewportBottom < topToElementEnd ) {
              options.toStick.addClass('sticky');
            }
          } else {
            options.toStick.removeClass('sticky');
          }

          if (topToViewportBottom > topToElementEnd ) {
            options.toStick
              .addClass('sticky-end')
              .removeClass('sticky')
              .css({top: (options.height - options.toStick.height() - options.offset) + 'px' });
          } else {
            options.toStick
              .removeClass('sticky-end')
              .removeAttr('style');
          }

         }
        $(window).scroll(onScroll);
        onScroll();
     });
  };