AngularJS Example

HTML

<div ng-app="">
        <input type="text" ng-model="example"/><br />
        <style>
            .ng-pristine {
                background-color: white;
            }  
            .ng-dirty {
                 background-color: red;
             }
         </style>
</div>

CSS

</style> <!-- Ugly Hack due to jsFiddle issue: http://goo.gl/BUfGZ --> 
<script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.0.6/angular.min.js"></script>
<style>