var app = angular.module('plunker', ['ngMobile']);

app.controller('MainCtrl', function($scope) {
  $scope.username = null;
  $scope.testClick = function() {
    alert('You clicked me!');
  };
});
<!DOCTYPE html>
<html ng-app="plunker">

  <head>
    <meta charset="utf-8" />
    <title>AngularJS Plunker</title>
    <script>document.write('<base href="' + document.location + '" />');</script>
    <link rel="stylesheet" href="style.css" />
    <script data-require="angular.js@1.1.x" src="http://code.angularjs.org/1.1.5/angular.min.js" data-semver="1.1.5"></script>
    <script data-require="angular-mobile.js@1.1.x" src="http://code.angularjs.org/1.1.5/angular-mobile.min.js" data-semver="1.1.5"></script>
    <script src="app.js"></script>
  </head>

  <body ng-controller="MainCtrl">
    <form name="testForm" novalidate>
      <p>ngMobile directive ignores the disabled state of the button</p>
      <p>Visit this page on a desktop browser and the disabled attribute of the button is respected</p>
      <p>Visit this page on a mobile browser and the disabled attribute of the button is ignored</p>
      <input type="text" name="username" id="username" ng-model="username" placeholder="Leave blank and click &rarr;" required />
    
      <button ng-click="testClick()" ng-disabled="!testForm.$valid">Click Me</button>
    </form>
  </body>

</html>
/* Put your css in here */