<!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">
<title>Document</title>
</head>
<style>
*{
margin: 0;
padding: 0;
}
.container{
position: relative;
top: 100px;
left: 50%;
transform: translateX(-50%);
background-color: #00CCFF;
width: 500px;
height: 350px;
}
.zhuce{
display: block;
height: 60px;
background-color: #0099CC;
color: white;
text-align: center;
font-weight: bold;
font-size: 24px;
line-height: 30px;
}
input{
margin-left: 90px;
display: block;
height: 40px;
width: 300px;
}
.c1{
margin-top: 40px;
}
.container div{
margin: 0px 100px;
height: 35px;
color: red;
font-size: 12px;
line-height: 35px;
}
button {
margin-left: 90px;
width: 300px;
height: 35px;
color: #fff;
background-color: #0099CC;
border: 1px solid grey;
cursor: pointer;
}
</style>
<body>
<div class="container">
<span class="zhuce">注册</span>
<input type="username" class="c1" id="username" placeholder="请输入您的用户名">
<div class="userNotice"></div>
<input type="password" id="password" placeholder="请输入您的密码">
<div class="passwordNotice"></div>
<button id='subBtn'>提交</button>
</div>
</body>
<script>
let username=document.getElementById('username')
let password=document.getElementById('password')
let userNotice=document.getElementsByClassName('userNotice')[0]
let passwordNotice=document.getElementsByClassName('passwordNotice')[0]
let sub=document.getElementById('subBtn')
sub.addEventListener('click',()=>{
let uValue = username.value
let keycode = uValue.charCodeAt(0)
userNotice.innerHTML = ''
if (uValue.length<6 || uValue.length>18) {
userNotice.innerHTML = '用户名长度必须为6到18位!'
} else if (keycode < 65 || (keycode > 90 && keycode < 97) || keycode > 122) {
userNotice.innerHTML = '用户名必须以英文字母开头!'
}
passwordNotice.innerHTML = ''
if (password.value.length < 6) {
passwordNotice.innerHTML = '密码不能少于六位!'
}
})
</script>
</html>
