<!DOCTYPE html>
<html>
<head>
<style>
form {background-color: #4040ff; border-radius: 20px; border: 1px solid #0; padding:0px 10px; position: relative; display: inline-block;}
form input[type="text"] {width: 150px; background-color: rgba(0, 0, 0, 0); border: medium none; color: #ffffff; -webkit-transition: width 1s; /* Safari */ ;transition: width 1s; direction: rtl; padding: 15px 0 15px 10px;}
form input[type="text"]:focus {width: 250px; border: medium none; outline: none; -webkit-transition: width 1s; /* Safari */ ;transition: width 1s;}
form input[type="submit"] {width: 1px; opacity: 0;}
</style>
</head>
<body>
<div>
<form>
<input type="text" placeholder="از این بخش جستجو کنید" name="s">
<input type="submit" value="">
</form>
</div>
</body>
</html>
