code: function currentYPosition() {
  	// Firefox, Chrome, Opera, Safari
  	if (self.pageYOffset) return self.pageYOffset;
  	// Internet Explorer 6 - standards mode
  	if (document.documentElement && document.documentElement.scrollTop)
  		return document.documentElement.scrollTop;
  	// Internet Explorer 6, 7 and 8
  	if (document.body.scrollTop) return document.body.scrollTop;
  	return 0;
  }
docs: /* Functions to manage the smooth scrool from the bottom to the top of the page