js进行表单验证实例分析

时间：2021-05-26

本文实例讲述了js进行表单验证的方法。分享给大家供大家参考。具体实现方法如下：

1. 传统的表单验证代码

复制代码 代码如下:<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>表单验证</title>
<script type="text/javascript">

function $(id) {
return document.getElementById(id);
}

function check() {
var email = $("email").value;
var password = $("password").value;
var repassword = $("repassword").value;
var name = $("name").value;

if(email == "") {
alert("Email值不能为空");
$("email").focus();
return false;
}

if(email.indexOf("@") == -1 || email.indexOf(".") == -1) {
alert("邮箱格式不正确,必须包含@和.");
$("email").focus();
return false;
}

if(password == "") {
alert("密码不能为空");
$("password").focus();
return false;
}

if(password.length < 6) {
alert("密码长度必须大于或者等于6");
$("password").focus();
return false;
}

if(repassword != password) {
alert("两次输入的密码不一致");
$("repassword").focus();
return false;
}

if(name == "") {
alert("姓名不能为空");
$("name").focus();
return false;
}

for(var i = 0; i < name.length; i++) {
var j = name.subString(i , i+1);
if(isNaN(j) == false) {
alert('姓名中不能包含数字');
$("name").focus();
return false;
}
}
}
</script>
</head>
<body>
<form name="login_form" method="post" onsubmit="return check()">
<div>
Email:<input type="text" name="email" id="email"/>
</div>
<div>
密码:<input type="password" name="password" id="password" />
</div>
<div>
重输密码:<input type="password" name="repassword" id="repassword" />
</div>
<div>
姓名：<input type="text" name="name" id="name" />
</div>
<div>
<input type="submit" value="注册" />
</div>
</form>
</body>
</html>

2. 输入框后面有提示信息的表单验证

复制代码 代码如下:<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>表单验证</title>
<script type="text/javascript">

function $(id) {
return document.getElementById(id);
}

function check() {
var email = $("email").value;
var password = $("password").value;
var repassword = $("repassword").value;
var name = $("name").value;

$("emailinfo").innerHTML = "";
$("passwordinfo").innerHTML = "";
$("repasswordinfo").innerHTML = "";
$("nameinfo").innerHTML = "";

if(email == "") {
$("emailinfo").innerHTML = "Email值不能为空";
$("email").focus();
return false;
}

if(email.indexOf("@") == -1 || email.indexOf(".") == -1) {
$("emailinfo").innerHTML = "邮箱格式不正确,必须包含@和.";
$("email").focus();
return false;
}

if(password == "") {
$("passwordinfo").innerHTML = "密码不能为空";
$("password").focus();
return false;
}

if(password.length < 6) {
$("passwordinfo").innerHTML = "密码长度必须大于或者等于6";
$("password").focus();
return false;
}

if(repassword != password) {
$("repasswordinfo").innerHTML = "两次输入的密码不一致";
$("repassword").focus();
return false;
}

if(name == "") {
$("nameinfo").innerHTML = "姓名不能为空";
$("name").focus();
return false;
}

for(var i = 0; i < name.length; i++) {
var j = name.subString(i , i+1);
if(isNaN(j) == false) {
$("nameinfo").innerHTML = '姓名中不能包含数字';
$("name").focus();
return false;
}
}
}
</script>
</head>
<body>
<form name="login_form" method="post" onsubmit="return check()">
<div>
Email:<input type="text" name="email" id="email"/><span id="emailinfo"></span>
</div>
<div>
密码:<input type="password" name="password" id="password" /><span id="passwordinfo"></span>
</div>
<div>
重输密码:<input type="password" name="repassword" id="repassword" /><span id="repasswordinfo"></span>
</div>
<div>
姓名：<input type="text" name="name" id="name" /><span id="nameinfo"></span>
</div>
<div>
<input type="submit" value="注册" />
</div>
</form>
</body>
</html>

效果图如下所示：

3. 在输入框失去焦点时触发校验函数
复制代码 代码如下:<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>表单验证</title>
<script type="text/javascript">
function $(id) {
return document.getElementById(id);
}

function check() {
var email = $("email").value;
var password = $("password").value;
var repassword = $("repassword").value;
var name = $("name").value;

$("emailinfo").innerHTML = "";
$("passwordinfo").innerHTML = "";
$("repasswordinfo").innerHTML = "";
$("nameinfo").innerHTML = "";

if(email == "") {
$("emailinfo").innerHTML = "Email值不能为空";
return false;
}

if(email.indexOf("@") == -1 || email.indexOf(".") == -1) {
$("emailinfo").innerHTML = "邮箱格式不正确,必须包含@和.";
return false;
}

if(password == "") {
$("passwordinfo").innerHTML = "密码不能为空";
return false;
}

if(password.length < 6) {
$("passwordinfo").innerHTML = "密码长度必须大于或者等于6";
return false;
}

if(repassword != password) {
$("repasswordinfo").innerHTML = "两次输入的密码不一致";
return false;
}

if(name == "") {
$("nameinfo").innerHTML = "姓名不能为空";
return false;
}

for(var i = 0; i < name.length; i++) {
var j = name.subString(i , i+1);
if(isNaN(j) == false) {
$("nameinfo").innerHTML = '姓名中不能包含数字';
return false;
}
}
}

function checkEmail() { //校验Email
$('emailinfo').innerHTML = "";
var email = $('email').value;
if(email == "") {
$('emailinfo').innerHTML = "Email值不能为空";
return false;
}

if(email.indexOf('@') == -1 || email.indexOf('.') == -1) {
$('emailinfo').innerHTML = "Email必须包含@和.";
return false;
}
}

function checkPassword() { //校验密码
$('passwordinfo').innerHTML = "";
var password = $('password').value;
if(password == "") {
$("passwordinfo").innerHTML = "密码不能为空";
return false;
}

if(password.length < 6) {
$("passwordinfo").innerHTML = "密码长度必须大于或者等于6";
return false;
}
}

function checkRepassword() { //校验重新输入的密码
$('repassword').innerHTML = "";
var repassword = $('repassword').value;
if(repassword != password) {
$("repasswordinfo").innerHTML = "两次输入的密码不一致";
return false;
}
}

function checkName() { //校验姓名
$('nameinfo').innerHTML = "";
var name = $('name').value;
if(name == "") {
$("nameinfo").innerHTML = "姓名不能为空";
return false;
}

for(var i = 0; i < name.length; i++) {
var j = name.subString(i , i+1);
if(isNaN(j) == false) {
$("nameinfo").innerHTML = '姓名中不能包含数字';
return false;
}
}
}
</script>
</head>
<body>
<form name="login_form" method="post" onsubmit="return check()">
<div>
Email:<input type="text" name="email" id="email" onblur="checkEmail();"/><span id="emailinfo"></span>
</div>
<div>
密码:<input type="password" name="password" id="password" onblur="checkPassword();"/><span id="passwordinfo"></span>
</div>
<div>
重输密码:<input type="password" name="repassword" id="repassword" onblur="checkRepassword();"/><span id="repasswordinfo"></span>
</div>
<div>
姓名：<input type="text" name="name" id="name" onblur="checkName();"/><span id="nameinfo"></span>
</div>
<div>
<input type="submit" value="注册" />
</div>
</form>
</body>
</html>

效果图如下所示：

希望本文所述对大家的javascript程序设计有所帮助。

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