var $el = (this.oldInstances.pop() || $('<div></div>').addClass('ui-widget-overlay'))
.appendTo(document.body)
.css({
width: this.width(),
height: this.height()
});
#在这下面增加
($.browser.msie && $.browser.version == '8.0')?$('body').css('overflow-x','hidden'):'';

this.maxZ = maxZ;
#在这下面增加
($.browser.msie && $.browser.version == '8.0')?$('body').css('overflow-x','auto'):'';