JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://twitter.github.com/bootstrap/assets/css/bootstrap.css">
<script src="http://code.jquery.com/jquery-1.7.2.js "></script>
<script src="http://underscorejs.org/underscore.js"></script>
<script src="http://documentcloud.github.com/backbone/backbone.js"></script>
<!DOCTYPE html>
<html>
    <head>
        <title>Backbone: Nested Views</title>
    </head>
    <body>
<div class="navbar">
    <div class="navbar-inner">
      <div class="container">
        <a class="btn btn-navbar" data-toggle="collapse" data-target=".nav-collapse">
          <span class="icon-bar"></span>
          <span class="icon-bar"></span>
          <span class="icon-bar"></span>
        </a>
        <a class="brand" href="#">Project name</a>
        <div class="nav-collapse">
          <ul class="nav">
            <li class="active"><a href="#">Home</a></li>
            <li><a href="#">Link</a></li>
            <li><a href="#">Link</a></li>
            <li><a href="#">Link</a></li>
            <li class="dropdown">
              <a href="#" class="dropdown-toggle" data-toggle="dropdown">Dropdown <b class="caret"></b></a>
              <ul class="dropdown-menu">
                <li><a href="#">Action</a></li>
                <li><a href="#">Another action</a></li>
                <li><a href="#">Something else here</a></li>
                <li class="divider"></li>
                <li class="nav-header">Nav header</li>
                <li><a href="#">Separated link</a></li>
                <li><a href="#">One more separated link</a></li>
              </ul>
            </li>
          </ul>
          <form class="navbar-search pull-left" action="">
            <input type="text" class="search-query span2" placeholder="Search">
          </form>
          <ul class="nav pull-right">
            <li><a href="#">Link</a></li>
            <li class="divider-vertical"></li>
            <li class="dropdown">
              <a href="#" class="dropdown-toggle"...

JavaScript

var LoginView = Backbone.View.extend({
    tagName: "form",
    className: "login well",
    template: $('#LoginTemplate').html(),
    render: function(){
        this.$el.html(this.template);
        return this;
    }
});

var RegistrationView = Backbone.View.extend({
    tagName: "form",
    className: "registration well",
    template: $('#RegistrationTemplate').html(),
    render: function(){
        this.$el.html(this.template);
        return this;
    }
});

var IndexView = Backbone.View.extend({
    tagName: "div",
    className: "container",
    template: _.template($("#LayoutTemplate").html()),
    render: function() {           
        var loginView = new LoginView();
        this.$el.html(this.template({ content: $("#ContentTemplate").html(), login: loginView.render().el }));
        return this;
    }
});

console.log(new IndexView.render().el);

$('div.main').html(new IndexView.render().el);