>功能:
点击Submit验证Username、Email、Password、ConfirmPassword
Username:字符长度6-12
Email:格式需为email格式
password:6-25字符
confirmpassword: 验证是否和password一致
验证成功:边框为绿色; 验证失败:边框为红色,显示相应报错信息
>HTML (文件名:index.html)
整个表单被一个大<div>
套起来,表单验证区域用<form>
套起来。
标题用<h2>
中间每一个验证框用<div>
套住,包含 <label for=’ ’>
(for中填的一般是和input相同的id名); <input id=‘’ placeholder=‘’>
placeholder表示未被填入时框内提示信息; <small>
错误提示内容区,此标签將使文本的字体变小一号,这个元素被重新定义为表示边注释和附属细则,包括版权和法律文本。
tips:class设置scc样式; id用来设置js
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link rel="stylesheet" href="./index.css">
<title>Form Validator</title>
</head>
<body>
<div class="container">
<form id="form" class="form">
<h2>Register With Us</h2>
<div class="form-control">
<label for="uesrname">Username</label>
<input type="text" placeholder="Enter username" id="username">
<small>Error message</small>
</div>
<div class="form-control">
<label for="Email">Email</label>
<input type="text" placeholder="Enter Email" id="email">
<small>Error message</small>
</div>
<div class="form-control">
<label for="password">Password</label>
<input type="password" placeholder="Enter Password" id="password">
<small>Error message</small>
</div>
<div class="form-control">
<label for="password2">Confirm password</label>
<input type="password" placeholder="Enter password again" id="password2">
<small>Error message</small>
</div>
<button type="submit">submit</button>
</form>
</div>
<script src="./script.js"></script>
</body>
</html>
>CSS (文件名:index.css)
💡技巧:声明全局变量
: root { (放在开头)
- - success-color: #2ecc71;
- - error-color: #e74c3c;
}
.form-control.success input { (引用公共颜色)
border-color: var(--success-color);
}
给<body>
设置flex
让表单居中;
给<form>
设置padding
使里面的内容可以对齐;
合理利用margin
(不装文字)和padding
(装文字)
设置<input>
样式:正常的边框颜色、报错边框(以及相应的<small>
)、正确边框
@import url('https://fonts.googleapis.com/css2?family=Open+Sans&display=swap');
:root {
--success-color: #2ecc71;
--error-color: #e74c3c;
}
* {
box-sizing: border-box;
}
body {
margin: 0;
min-height: 100vh;
background-color: #f8fafb;
display: flex;
justify-content: center;
align-items: center;
font-family: 'Open Sans', sans-serif;
}
.container {
width: 400px;
border-radius: 5px;
background-color: #fff;
box-shadow: 0 2px 10px rgba(0,0,0,0.3);
}
h2 {
text-align: center;
margin: 0 0 20px; /*上 左右 下 */
}
form {
padding: 30px 40px;
}
.form-control {
padding-bottom: 20px;
margin-bottom: 10px;
position: relative;
}
.form-control label {
display: block;
margin-bottom: 5px;
color: #777;
}
.form-control input {
display: block;
border: 2px solid #f0f0f0;
border-radius: 4px;
width: 100%;
padding: 10px;
font-size: 14px;
}
.form-control input:focus {
outline: 0;
border-color: #777;
}
.form-control.success input{
border-color: var(--success-color);
}
.form-control.error input{
border-color: var(--error-color);
}
.form-control small {
color: var(--error-color);
position: absolute;
bottom: 0;
left: 0;
visibility: hidden; /*display: none 会改变布局; */
}
.form-control.error small {
visibility: visible;
}
.form button {
display: block;
font-size: 16px;
padding: 10px;
width: 100%;
margin-top: 20px;
color: #fff;
background-color: #3498db;
border: 2px solid #3498db;
border-radius: 2px;
cursor: pointer;
}
>JavaScript (文件名: script.js)
采取先函数封装,然后在事件监听器里调用函数的形式更清晰
注意:<button>在<form>里会导致点击刷新,解决办法是给事件监听器添加e事件,然后 e.preventDefult(e) 阻止默认事件发生;
const form = document.getElementById('form');
const username = document.getElementById('username');
const email = document.getElementById('email');
const password = document.getElementById('password');
const password2 = document.getElementById('password2');
// Show error input message (显示错误信息)
function showError(input, message) {
const formControl = input.parentElement;
formControl.className = 'form-control error';
const small = formControl.querySelector('small');
small.innerText = message;
}
//Show sucsess outline (显示成功)
function showSuccess(input) {
const formControl = input.parentElement;
formControl.className = 'form-control success';
}
// Check required fields (检查是否输入了信息)
function checkRequired(inputArr) {
inputArr.forEach(function(input) {
if(input.value.trim() === '') {
showError(input, `${getFieldName(input)} is required`)
}
})
}
//check input length (检查输入信息的长度)
function checkLength(input, min, max) {
if (input.value.length < min) {
showError(input, `${getFieldName(input)} must be at least ${min} characters`);
} else if (input.value.length > max) {
showError(input, `${getFieldName(input)} must be less than ${max} characters`);
} else {
showSuccess(input);
}
}
//Check email is valid (检查email格式)(箭头函数方法怎么用)
function checkEmail(input) {
const re = /^(([^<>()[\]\\.,;:\s@"]+(\.[^<>()[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;
if (re.test(input.value)) {
showSuccess(input)
} else {
showError(input, 'Email is not valid')
}
}
// Check password match (检查二次确认密码是否匹配)
function checkPasswordsMatch(input1, input2) {
if (input1.value !== input2.value) {
showError(input2, 'Passsword do not match')
} else {
showSuccess(input2)
}
}
// Get fieldname (首字母大写函数)
function getFieldName(input) {
return input.id.charAt(0).toUpperCase() + input.id.slice(1);
}
//Event listener (事件监听器调用函数)
form.addEventListener('submit', function(e) {
e.preventDefault(e);
checkRequired([username, email, password, password2])
checkLength(username, 3, 15);
checkLength(password, 6, 25);
checkEmail(email);
checkPasswordsMatch(password, password2);
})