function makeScrollable(wrapper, scrollable) {

  var wrapper = $(wrapper), scrollable = $(scrollable);

  wrapper.css({ overflow: 'hidden' });



  var inactiveMargin = 99;

  var wrapperWidth = wrapper.width();

  var wrapperHeight = wrapper.height();

  var scrollableHeight = scrollable.outerHeight() + 2 * inactiveMargin;



  wrapper.mousemove(function(e) {

    var wrapperOffset = wrapper.offset();

    var top = (e.pageY - wrapperOffset.top) * (scrollableHeight - wrapperHeight) / wrapperHeight - inactiveMargin;

    if (top < 0) top = 0;

    wrapper.scrollTop(top);

  });

}



$(document).ready(function() {

  makeScrollable("div.sc_menu_wrapper", "div.sc_menu");

});