<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<script>
/**
* 生成 n 位的验证码
* n : 表示要成的位数
* 返回值：按要求生成的验证码
*/
function generalCode(n){
var code = [0,1,2,3,4,5,6,7,8,9,'a','b','c','d','e','A','B','C','D','E'];
var str = "";
for(var i=0;i<n;i++){
//随机生成 0-(code.length-1) 的验证码
var r = parseInt(Math.random() * code.length);
str += code[r];
}
return str;
}
function testValidateCode(){
var str = generalCode(6);
var input = prompt("请输入以下验证码:"+str);
if(input.toUpperCase() == str.toUpperCase()){
alert("验证通过");
}else{
alert("验证失败");
}
}
/**
* 使用 indexOf 和 lastIndexOf 验证邮箱格式
*/
function validateEmail(){
var email = prompt("请输入电子邮箱:");
var atIndex = email.indexOf("@");
var dotIndex = email.indexOf(".");
var lastDotIndex = email.lastIndexOf(".");
if(atIndex >= 0 && dotIndex >= 0 && lastDotIndex > atIndex){
alert("格式正确");
}else{
alert("格式错误");
}
}
function testSubstring(){
var email = "sanfeng.zhang@sina.com";
var uname = email.substring(0,email.indexOf("@"));
console.log("用户名为:"+uname);
var server = email.substring(email.indexOf("@")+1,email.lastIndexOf("."));
console.log("服务商名称："+server);
}
</script>
<button onclick="testValidateCode()">验证码</button>
<button onclick="validateEmail()">验证邮件</button>
<button onclick="testSubstring()">截取子字符串</button>
</body>
</html>
