<form ng-app="myApp" ng-controller="validateCtrl" 
name="myForm" novalidate>

<p>用户名:<br>
<input type="text" name="user" ng-model="user" required>
<span class="alert alert-danger" ng-show="myForm.user.$dirty && myForm.user.$invalid">
<span ng-show="myForm.user.$error.required">用户名是必须的。</span>
</span>
</p>

<p>邮箱:<br>
<input type="email" name="email" ng-model="email" required>
<span class="alert alert-danger" ng-show="myForm.email.$dirty && myForm.email.$invalid">
<span ng-show="myForm.email.$error.required">邮箱是必须的。</span>
<span ng-show="myForm.email.$error.email">非法的邮箱地址。</span>
</span>
</p>

<p>
<input type="submit"
ng-disabled="myForm.user.$dirty && myForm.user.$invalid ||  
myForm.email.$dirty && myForm.email.$invalid">
</p>

</form>

<script>
var app = angular.module('myApp', []);
app.controller('validateCtrl', function($scope) {
    $scope.user = 'John Doe';
    $scope.email = '[email protected]';
});
</script>