JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://static.firebase.com/v0/firebase.js"></script>
<script src="http://katowulf.thoughtbin.org/angularFire.js"></script>
<div ng-app ng-controller="ctrl">
    <form name="registerForm" class="form-horizontal">
        <div class="control-group">
            <label class="control-label">שם פרטי</label>
            <div class="controls">
                <input type="text" name="firstName" ng-model="register.firstName" placeholder="שם פרטי" required ng-pattern="pattern">{{registerForm.firstName.$valid}}</div>
        </div>
       
    </form>
</div>

JavaScript

function ctrl($scope) {
    $scope.pattern = /[\u0590-\u05FF]+/g;
}