直接上演示效果和代码， 不多讲
演示效果：
代码
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title></title>
<style>
body {
background-image: url('https://p3-juejin.byteimg.com/tos-cn-i-k3u1fbpfcp/7bfed17aeb2c4734ab59e471292549d7~tplv-k3u1fbpfcp-watermark.image');
background-repeat: no-repeat;
background-size: 100%;
background-position: 0px -50px;
}
.login-box {
position: absolute;
top: 50%;
left: 50%;
width: 400px;
padding: 40px;
transform: translate(-50%, -50%);
background: rgba(0, 0, 0, .5);
box-sizing: border-box;
box-shadow: 0 15px 25px rgba(0, 0, 0, .6);
border-radius: 10px;
}
.login-box h2 {
margin: 0 0 30px;
padding: 0;
color: #fff;
text-align: center;
}
.login-box .user-box {
position: relative;
}
.login-box .user-box input {
width: 100%;
padding: 10px 0;
font-size: 16px;
color: #fff;
margin-bottom: 30px;
border: none;
border-bottom: 1px solid #fff;
outline: none;
background: transparent;
}
.login-box .user-box label {
position: absolute;
top: 0;
left: 0;
padding: 10px 0;
font-size: 16px;
color: #fff;
pointer-events: none;
transition: .5s;
}
.login-box .user-box input:focus~label,
.login-box .user-box input:valid~label {
top: -20px;
left: 0;
color: #03e9f4;
font-size: 12px;
}
.login-box form a {
position: relative;
display: inline-block;
padding: 10px 20px;
color: #03e9f4;
font-size: 16px;
text-decoration: none;
text-transform: uppercase;
overflow: hidden;
transition: .5s;
margin-top: 40px;
letter-spacing: 4px
}
.login-box a:hover {
background: #03e9f4;
color: #fff;
border-radius: 5px;
box-shadow: 0 0 5px #03e9f4,
0 0 25px #03e9f4,
0 0 50px #03e9f4,
0 0 100px #03e9f4;
}
.login-box a span {
position: absolute;
display: block;
}
.login-box a span:nth-child(1) {
top: 0;
left: -100%;
width: 100%;
height: 2px;
background: linear-gradient(90deg, transparent, #03e9f4);
animation: btn-anim1 1s linear infinite;
}
@keyframes btn-anim1 {
0% {
left: -100%;
}
50%,
100% {
left: 100%;
}
}
.login-box a span:nth-child(2) {
top: -100%;
right: 0;
width: 2px;
height: 100%;
background: linear-gradient(180deg, transparent, #03e9f4);
animation: btn-anim2 1s linear infinite;
animation-delay: .25s
}
@keyframes btn-anim2 {
0% {
top: -100%;
}
50%,
100% {
top: 100%;
}
}
.login-box a span:nth-child(3) {
bottom: 0;
right: -100%;
width: 100%;
height: 2px;
background: linear-gradient(270deg, transparent, #03e9f4);
animation: btn-anim3 1s linear infinite;
animation-delay: .5s
}
@keyframes btn-anim3 {
0% {
right: -100%;
}
50%,
100% {
right: 100%;
}
}
.login-box a span:nth-child(4) {
bottom: -100%;
left: 0;
width: 2px;
height: 100%;
background: linear-gradient(360deg, transparent, #03e9f4);
animation: btn-anim4 1s linear infinite;
animation-delay: .75s
}
@keyframes btn-anim4 {
0% {
bottom: -100%;
}
50%,
100% {
bottom: 100%;
}
}
</style>
</head>
<body>
<div>
<div class="login-box">
<h2>图书管理系统</h2>
<form id="f1">
<div class="user-box">
<input type="text" name="" required="" >
<label>账号</label>
</div>
<div class="user-box">
<input type="password" name="" required="" >
<label>密码</label>
</div>
<a onclick="handleSubmit()">
<span></span>
<span></span>
<span></span>
<span></span>
登录
</a>
<a onclick="torig()">去注册</a>
</form>
<form id="f2" style="display:none;">
<div class="user-box">
<input type="text" name="" required="" >
<label>账号</label>
</div>
<div class="user-box">
<input type="password" name="" required="" >
<label>验证码</label>
</div>
<div class="user-box">
<input type="password" name="" required="" >
<label>密码</label>
</div>
<a onclick="check()">
<span></span>
<span></span>
<span></span>
<span></span>
获取验证码
</a>
<a onclick="rig()">
<span></span>
<span></span>
<span></span>
<span></span>
注册
</a>
<p onclick="toLogin()" style="text-align: right;color:#03e9f4;">已有账号，去登陆</p>
</form>
</div>
</div>
<script type="text/javascript">
let f1 = document.getElementById("f1")
let f2 = document.getElementById("f2")
function handleSubmit(){
}
function torig(){
f2.style.display = 'block'
f1.style.display = 'none'
}
function rig(){
}
function toLogin(){
f1.style.display = 'block'
f2.style.display = 'none'
}
function check(){
}
</script>
</body>
</html>
