计算页面尺寸收集

function(){
	return{
		top:function(){return document.documentElement.scrollTop||document.body.scrollTop},
		width:function(){return self.innerWidth||document.documentElement.clientWidth||document.body.clientWidth},
		height:function(){return self.innerHeight||document.documentElement.clientHeight||document.body.clientHeight},
		total:function(d){
			var b=document.body, e=document.documentElement;
			return d?Math.max(Math.max(b.scrollHeight,e.scrollHeight),Math.max(b.clientHeight,e.clientHeight)):
			Math.max(Math.max(b.scrollWidth,e.scrollWidth),Math.max(b.clientWidth,e.clientWidth))
		}
	}
}();