console 命令行工具 X clear

console

var box = document.getElementById("box"); 
var span = document.getElementsByTagName("span"); 
var btn = document.getElementById("btn"); 
var color = ""; 
var str = "0123456789abcdef"; 
btn.onclick = function () { for (var i = 0; i < span.length; i++) {
    //生成四位数 
    for(var j=0;j<6;j++){
        //随机改变每个数字的颜色 
        color+=str.substr(parseInt(Math.random()*str.length),1);
        //取颜色(循环，每次提取一位，进行拼接组成6为颜色的值)
         } span[i].innerHTML=parseInt(Math.random()*10);
         //生成随机数 
         span[i].style.color=("#"+color);
         //随机改变每个span的颜色 
         color=""; } }

<!DOCTYPE html>
<html>

<head>
	<meta charset="UTF-8"> <title></title>
	<style>
	</style>
</head>

<body>
	<div id="box">
		<span>1</span> 
    <span>2</span> 
    <span>3</span> 
    <span>4</span> 
    </div> 
    <input type="button" id="btn" value="我变了哟！"/>
    </body> 
    </html>

		#box {
			margin: 100px auto;
			width: 200px;
			height: 150px;
			line-height: 150px;
			letter-spacing: 10px;
			text-align: center;
			font-size: 30px;
			font-weight: bolder;
			border: 2px solid palegreen;
			word-wrap: break-word;
			border-radius: 5px;
			;
			position: relative;
		}

		#btn {
			position: absolute;
			left: 50%;
			top: 280px;
		}