关于ie8获取高度和其他不一样
var userAgent = navigator.userAgent; //取得浏览器的userAgent字符串
if (userAgent.indexOf("compatible") > -1 && userAgent.trim().replace(/[ ]/g,"").indexOf("MSIE8.0") > -1) { return { top: ((window.innerHeight||(document.documentElement&&document.documentElement.clientHeight)||document.body.clientHeight - this.messi.height()) / 2) + jQuery(window).scrollTop()+ "px", left: ((window.innerWidth||(document.documentElement&&document.documentElement.clientWidth)||document.body.clientWidth - this.messi.width()) / 2) + jQuery(window).scrollLeft()+ "px" }; }else{ return { top: ((jQuery(window).height() - this.messi.height()) / 2) + jQuery(window).scrollTop() + "px", left: ((jQuery(window).width() - this.messi.width()) / 2) + jQuery(window).scrollLeft() + "px" }; }