点击创建效果 | 点击创建

原生：点击创建div，且能够拖动

css、html

	<style type="text/css">
		.active{
			width: 100px;
			height: 100px;
			position: absolute;
		}
	</style>
	<body>
		<input type="button" value="创建div" id="oBtn" />
	</body>

<script src="public.js"></script>
<script>
	var btn = document.getElementById("oBtn");
	btn.onclick = function(){
		new DragDiv().init()
	}

	function DragDiv(){
		this.div = document.createElement("div");
		this.init = function(){
			document.body.appendChild(this.div);
			this.div.className = "active";
			this.div.style.left = rand(0,window.innerWidth - 100) + "px";
			this.div.style.top = rand(0,window.innerHeight - 100) + "px";
			this.div.style.background = getColor();
			this.drag();
		}
		this.drag = function(){
			//这里的this还是实例
			this.div.onmousedown = function(e){
				e = e || event;
				this.down(e);
				document.onmousemove = function(e){
					e = e || event;
					this.move(e);
				}.bind(this)
				document.onmouseup = function(){
					this.up();
				}.bind(this);
				return false;
			}.bind(this)
		}
		this.down = function(e){
			this.disX = e.offsetX;
			this.disY = e.offsetY;
		}
		this.move= function(e){
			this.div.style.left = e.pageX - this.disX + "px";
			this.div.style.top = e.pageY - this.disY + "px";
		}
		this.up = function(){
			document.onmousemove = null;
		}
	}
</script>

　　public.js

function $id(id){//给我一个id名，返回一个这个id的元素
	return document.getElementById(id);
}
//求随机数
function rand(min,max){
	return Math.round(Math.random()*(max - min) + min);
}

//随机的16进制颜色
function getColor(){
	var str = "0123456789ABCDEF";//十六进制字符串
	var color = "#";
	for(var i = 0; i <= 5; i++){//取6个数
		color += str.charAt(rand(0,15));
		//rand(0,15)随机0-15之间的数，作为charAt()的下标，取出下标对应的字符
	}
	return color;
}
function zero(val){
	return val < 10 ? "0" + val : val;
}
//时间差
function diff(start,end){//2000-2018  2018 - 2000
	//console.log(start.getTime());
	return Math.abs(start.getTime() - end.getTime())/1000;
}