<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
</head>
<body>
<button onclick="validate();">点击输入</button>
<script type="text/javascript">
//1.生成随机任意位验证码
function createCode(len) {
var arr = ['w','e','r','t','y','u','i','o','p','A','S','D','F','G','H','J','K','L',0,1,2,3,4,5,6,7,8,9] //码源
var show=" "
for(var i=0;i<len;i++){
//生成随机下标
var index = parseInt(Math.random()*arr.length)
show += arr[index]
}return show
}
function validate(){
//生成验证码
var code = createCode(6)
//提示输入并验证
var input=prompt("请输入验证码(不区分大小写):"+code)
if(input.toUpperCase()==code.toUpperCase()){
alert("输入正确")
}else{
alert("输入有误")
}
}
</script>
</body>
</html>