老师请问我这段代码为啥没效果呢

来源：3-5 html5约束验证API之validity演示

qq_慕九州2374973

2020-02-21 17:39:41

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>2test</title>
    <style>
        input[type="search"]::-webkit-search-cancel-button{
            -webkit-appearance: none;
            height: 15px;
            width: 15px;
            background-color: #f01414;
        }
    </style>
</head>
<body>
<form action="" method="get">
    <input type="text" id="username" value="s" pattern="^\d{5}">
    <input type="search" id="search" value="">
    <input type="submit">
</form>
<script>
    // console.log(document.getElementById("username") === username);
</script>
</body>
</html>

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