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How to make verification code in javascript
- 王林Original
- 2021-10-26 16:54:073546browse
Javascript method to create verification code: [var code; window.onload = function creatCode() { code=""; var codeLength = 4; var checkCode = ...}].
#The operating environment of this article: windows10 system, javascript 1.8.5, thinkpad t480 computer.
Use javascript to implement the login verification code function. The following is the specific implementation code:
test.html
<!DOCTYPE html> <html> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <head> <title>验证码</title> <script src = "checkCode.js"> </script> </head> <body> <div> <input type = "text" id = "input"/> <input type = "button" id="code" οnclick="createCode()"/> <input type = "button" value = "验证" onclick = "validate()"/> </div> </body> </html>
checkCode.js
var code ; //在全局定义验证码
window.onload = function createCode(){
code = "";
var codeLength = 4;//验证码的长度
var checkCode = document.getElementById("code");
var random = new Array(0,1,2,3,4,5,6,7,8,9,'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');//随机数
for(var i = 0; i < codeLength; i++) {//循环操作
var index = Math.floor(Math.random()*36);//取得随机数的索引（0~35）
code += random[index];//根据索引取得随机数加到code上
}
checkCode.value = code;//把code值赋给验证码
}
//校验验证码
function validate(){
var inputCode = document.getElementById("input").value.toUpperCase(); //取得输入的验证码并转化为大写
if(inputCode.length <= 0) { //若输入的验证码长度为0
alert("Empty Code!"); //则弹出请输入验证码
}
else if(inputCode != code ) { //若输入的验证码与产生的验证码不一致时
alert("Error Code"); //则弹出验证码输入错误
createCode();//刷新验证码
document.getElementById("input").value = "";//清空文本框
}
else { //输入正确时
alert("OK"); //弹出^-^
}
}When clicked Code that does not move the position:
<p class="red"><a href="javascript:;" οnclick="createCode()">看不清？</a></p>
Recommended learning: javascript video tutorial
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