console 命令行工具 X clear

console

window.onscroll=function() {
		var oDiv=document.getElementById('div1');
		var scrollTop=document.documentElement.scrollTop||document.body.scrollTop;
		//oDiv.style.top=document.documentElement.clientHeight-oDiv.offsetHeight+scrollTop+'px';
		startMove(document.documentElement.clientHeight-oDiv.offsetHeight+scrollTop);
    }
	var timer=null;
	function startMove(iTarget) {
		var oDiv=document.getElementById('div1');
		clearInterval(timer);
		timer=setInterval(function() {
			var speed;
			speed=(iTarget-oDiv.offsetTop)/10;
			speed=speed>0?Math.ceil(speed):Math.floor(speed);
			oDiv.style.top=oDiv.offsetTop+speed+'px';
		},30);
	}

<body style="height: 3000px;">
<div id="div1"></div>

#div1 {width: 100px; height: 150px; background: red; position: absolute; bottom: 0; right: 0;}