HTML登陆成功后怎么跳转到主页面呀？

<div class="log">
        <form action="登录.php" method="post">
            <label for="">用户名label>
            <input type="text" name="username" id="" placeholder="请输入您的用户名">
            <br>
            <br>
            <label for="">密码：label>
            <input type="password" name="passwd" id="" placeholder="请输入您的密码">
            <br>
            <br>
            <button type="submit">提交button>
        form>
    div>

window.location.href