使用JavaScript怎么实现一个生成4位随机验证码功能？相信很多没有经验的人对此束手无策，为此本文总结了问题出现的原因和解决方法，通过这篇文章希望你能解决这个问题。
代码：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
<style>
div {
width: 100px;
height: 50px;
background: red;
text-align: center;
line-height: 50px;
}
</style>
</head>
<body>
<div id="yzm"></div>
<button id="btn">点击生成验证码</button>
<script>
// var str = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
//数组转换为字符串
// var arr = str.split("");
var arr = ["a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z", "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z", "0", "1", "2", "3", "4", "5", "6", "7", "8", "9"];
// console.log(arr);
//页面刚加载时候调用它
sjs(arr);
btn.onclick = function() {
sjs(arr);
}
function sjs(arr) {
var code = Math.floor(Math.random() * arr.length);
var code1 = Math.floor(Math.random() * arr.length);
var code2 = Math.floor(Math.random() * arr.length);
var code3 = Math.floor(Math.random() * arr.length);
var n = arr[code] + arr[code1] + arr[code2] + arr[code3];
yzm.innerHTML = n
}
</script>
</body>
</html>小编再为大家分享一段代码：点击产生四位随机数字母与数字
<!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>点击产生随机数</title>
<style>
span{
display: block;
width: 110px;
height: 50px;
border: 1px solid red;
text-align: center;
line-height: 50px;
}
</style>
</head>
<body>
<span id="demo" onclick="init();"></span>
<script>
init();
function init(){
var arr=[];
for(var i=48;i<123;i++){
if(i>57 && i<65) continue;
if(i>90 && i<97) continue;
arr.push(String.fromCharCode(i));
}
arr.sort(function () {
return Math.random()-0.5;
});
arr.length=4;
var span= document.getElementById('demo');
span.textContent=(arr.join(""));
}
</script>
</body>
</html>看完上述内容，你们掌握使用JavaScript怎么实现一个生成4位随机验证码功能的方法了吗？如果还想学到更多技能或想了解更多相关内容，欢迎关注亿速云行业资讯频道，感谢各位的阅读！
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