HTML: Bootstrap - simple login

gistfile1

<form class="form-horizontal" action='' method="POST">
    <fieldset>
        <div id="legend">
            <legend class="">Login</legend>
        </div>
        <div class="control-group">
            <!-- Username -->
            <label class="control-label" for="username">Username</label>
            <div class="controls">
                <input type="text" id="username" name="username" placeholder="" class="input-xlarge"></div>
        </div>

        <div class="control-group">
            <!-- Password-->
            <label class="control-label" for="password">Password</label>
            <div class="controls">
                <input type="password" id="password" name="password" placeholder="" class="input-xlarge"></div>
        </div>

        <div class="control-group">
            <!-- Button -->
            <div class="controls">
                <button class="btn btn-success">Login</button>
            </div>
        </div>
    </fieldset>
</form>