JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://twitter.github.com/bootstrap/assets/css/bootstrap.css">
<script src="http://twitter.github.com/bootstrap/assets/js/bootstrap-dropdown.js"></script>
<div class="navbar navbar-fixed-top">
<div class="navbar-inner">
    <div class="container">
        <ul class="nav">
            <li><a href="#">Home</a></li>
            <li><a href="#">Section1</a></li>
            <li><a href="#">Section2</a></li>
        </ul>

        <ul class="nav nav-tabs pull-right signin-menu">
            <li class="dropdown" data-dropdown="dropdown"><a href="#" data-toggle="dropdown" class="login-link dropdown-toggle">Login</a>
                <ul class="dropdown-menu" id="signin-dropdown">
                    <li>
                        <form>....</form>
                    </li>
                </ul>
            </li>   
        </ul>           
    </div>
</div>

CSS

.signin-menu .dropdown-menu:before {
    display: none;
}

.signin-menu .dropdown-menu:after {
    display: none;
}

JavaScript

$('.dropdown-toggle').dropdown()