js控制横向滚动条居中，鼠标在页面中的坐标

/**横向滚动条居中**/    var value=(1920-$(window).width())/2;    $(window).scrollLeft(value);/**鼠标在屏幕坐标兼容火狐**/    function getMousePos(event) {      var e = event || window.event;      var scrollX = document.documentElement.scrollLeft || document.body.scrollLeft;      var scrollY = document.documentElement.scrollTop || document.body.scrollTop;      var Point_X = e.pageX || e.clientX + scrollX;      var Point_Y = e.pageY || e.clientY + scrollY;      return { 'Point_X': Point_X, 'Point_Y': Point_Y };    }