JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://netdna.bootstrapcdn.com/twitter-bootstrap/2.3.2/css/bootstrap-combined.min.css">
<div ng-app ng-controller="Ctrl">
    <ng-form name="fOuter">
        <h3>Outer form (valid={{!fOuter.txtOuter.$error.required}})</h3>
        <input type="text" name="txtOuter" ng-model="outer" placeholder="(required)" required />
        <ng-form name="fInner">
            <h3>Inner form (valid={{fInner.$valid}})</h3>
            <input type="text" name="txtInner" ng-model="inner" placeholder="(required)" required />
        </ng-form>
    </ng-form>
</div>

JavaScript

function Ctrl($scope) {
    $scope.outer = "text"
}