查看滚动条距离，原型封装

function getscrollOffset(){
	if(window.pageXoffset){
		return{
			left:pageXoffset,
			 top:pageYoffset;
		}
	}else{
		return{
			left: document.body.scrollLeft + document.documentElement.scrollLeft,
			top:document.body.scrollTop + document.documentElement.scrollTop
		}
	}
}

获取浏览器窗口的尺寸

function getScrollSize(){
	if(document.body.scrollWidth){
		return{
			width: document.body.scrollwidth,
			height: document.body.scrollHeight
		}
	}else{
		return{
			width: docuemnt.documentElement.scrollWidth,
			height: document.documentElement.scrollHeight
		}
	}
}

获取元素和属性的宽高

function getStyles(elem,prop){
	if(window.getComputedStyle){
		if(prop){
			return window.getComputedStyle(elem,null)[prop];
		}else{
			return window.getComputedStyle(elem,null);
		}else{
			if(prop){
				return elem.currentStyle[prop];
			}else{
				if(prop){return elem.currentStyle[prop];
			}else{
				return elem.currentStyle
			}
		}
	}
}