om scrolling the body
  this.$toc.addEventListener('wheel', function (e) {
    var target = e.currentTarget;
    var offTop = e.deltaY < 0 && target.scrollTop === 0;
    if (offTop) {
      e.preventDefault();
    }
    var offBottom = e.deltaY > 0
                    && target.offsetHeight + target.scrollTop >= target.scrollHeight;

    if (offBottom) {
		  e.preventDefault();
	  }
  })
}

Menu.prototype.documentKeydown = function (e) {
  e.stopPropagation();
  if (e.keyCode === 80) {
    this.togglePinEnt