先上图
代码
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>css 输入框动效</title>
<style>
.inputBox {
position: relative;
width: 250px;
}
.inputBox input {
width: 100%;
padding: 10px;
border: 1px solid #cccccc;
border-radius: 5px;
font-size: 1em;
outline: none;
}
.inputBox span {
position: absolute;
left: 0;
top: 0;
padding: 10px;
font-size: 1em;
pointer-events: none;
color: #cccccc;
}
.inputBox input:valid ~ span,
.inputBox input:focus ~ span {
color: orangered;
transform: translateX(10px) translateY(-7px);
font-size: 0.65em;
padding: 0 10px;
background: #ffffff;
}
</style>
</head>
<body>
<div class="inputBox">
<input type="text" required/>
<span>用户名</span>
</div>
</body>
</html>
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