版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/lengyuezuixue/article/details/82154363
<!DOCTYPE html >
<html>
<head>
<meta charset="utf-8">
<title>自学教程(如约智惠.com)</title>
<style >
input[type=text] {
width: 130px;
box-sizing: border-box;
border: 2px solid #ccc;
border-radius: 4px;
font-size: 16px;
background-color: white;
background-image: url('searchicon.png');
background-position: 10px 10px;
background-repeat: no-repeat;
padding: 12px 20px 12px 40px;
-webkit-transition: width 0.4s ease-in-out;
transition: width 0.4s ease-in-out;
}
input[type=text]:focus {
width: 100%;
}
</style>
</head>
<body >
<h1>动态搜索框：</h1>
<form>
<input type="text" name="search" placeholder="搜索..">
</form>
</body>
</html>