Angular实现了大部分常用的HTML5的表单控件的类型(text, number, url, email, date, radio, checkbox)，也实现了很多指令做为验证(required, pattern, minlength, maxlength, min, max)。
在自定义的指令中，我们可以添加我们的验证方法到ngModelController的$validators对象上。为了取得这个controller对象，我们需要requirengModel指令。
在$validators对象上的每个方法都接收modelValue和viewValue两个值做为参数。在你绑定的验证方法返回一个值(true,false)之后，Angular会在内部调用$setValidity方法。验证会在每一次输入框的值改变($setViewValue被调用)或者模型的值改变。验证发生在$parsers和$formatters成功运行之后，验证不通过的项会做为ngModelController.$error的属性存储起来。
另外，在这个controller对象上，还有一个$asyncValidators对象，如果你的验证是异步的，则需要加验证附加在这个对象上，比如说用户注册时输入手机号，我们需要在后端验证该手机号是否已经注册，这个验证方法必须return一个promise对象，然后在验证通过时调用延迟对象的resolve，失败时调用reject，还未完成的异步的验证存储在ngModelController.$pending中。

例如(注意其中的user对象，只有验证通过了，才会将值绑定到模型上):

<form name="register_form" ng-submit="save()">  <div class="form-group">  <label for="phoneNumber">  手机号(不能重复):  </label>  <input type="text" class="form-control" ng-model="user.phoneNumber" id="phoneNumber" name="phoneNumber" required phone>  </div>  <div class="form-group">  <label for="username">  用户名(必须大于五位):  </label>  <input type="text" class="form-control" ng-model="user.username" id="username" required username>  </div>  <button class="btn btn-block btn-primary" type="submit">提交</button>
</form>
<h3>用户对象</h3>
<pre>  {{ user | json }}
</pre>  

'use strict';
angular.module('app', [])  .directive('phone', function ($q, $http) {  return {  require: 'ngModel',  link: function (scope, ele, attrs, ctrl) {  ctrl.$asyncValidators.phone = function (modelValue, viewValue) {  var d = $q.defer();  $http.get('phone.json')  .success(function (phoneList) {  if (phoneList.indexOf(parseInt(modelValue)) >= 0) {  d.reject();  } else {  d.resolve();  }  });  return d.promise;  }  }  }
})  .directive('username', function ($q, $http) {  return {  require: 'ngModel',  link: function (scope, ele, attrs, ctrl) {  ctrl.$validators.username = function (modelValue, viewValue) {  if (modelValue) {  return modelValue.length > 5 ? true : false;  };  return false;  }  }  }
})  

[  13758262732,  15658898520,  13628389818,  18976176895,  13518077986
]  

效果:

下面一个完整的用户注册的表单验证:
html:

<form name="register_form" novalidate>  <div class="form-group">  <label for="username">用户名:</label>  <!-- ng-pattern="/PATTERN/"确保输入项符合正则 -->  <input type="text" id="username" ng-model="user.username" class="form-control" name="username" required ng-pattern="/^[^#]*$/">  <span class="glyphicon glyphicon-ok right" ng-show="register_form.username.$valid"></span>  </div>  <div class="alert alert-danger" ng-show="register_form.username.$error.pattern">  <strong>请注意！</strong>  用户名不能带#号。  </div>  <div class="alert alert-danger" ng-show="register_form.username.$error.required && register_form.username.$touched">  <strong>请注意！</strong>  用户名不能为空。  </div>  <div class="form-group">  <label for="_password">密码:</label>  <!-- ng-minlength="num"让密码不能小于最小长度 -->  <input type="password" id="_password" ng-model="data._password" class="form-control" required ng-minlength="8" name="_password">  <span class="glyphicon glyphicon-ok right" ng-show="register_form._password.$valid"></span>  </div>  <div class="alert alert-danger" ng-show="register_form._password.$error.minlength && register_form._password.$touched">  <strong>请注意！</strong>  密码长度不能少于八位。  </div>  <div class="alert alert-danger" ng-show="register_form._password.$error.required && register_form._password.$touched">  <strong>请注意！</strong>  密码不能为空。  </div>  <div class="form-group">  <label for="password">确认密码:</label>  <input type="password" id="password" ng-model="user.password" class="form-control" name="password" required pwd-repeat>  <span class="glyphicon glyphicon-ok right" ng-show="register_form.password.$valid"></span>  </div>  <div class="alert alert-danger" ng-show="register_form.password.$error.pwdRepeat && register_form.password.$touched">  <strong>请注意！</strong>  两次输入的密码不相同。  </div>  <div class="alert alert-danger" ng-show="register_form.password.$error.required && register_form.password.$touched">  <strong>请注意！</strong>  请再次输入密码。  </div>  <div class="form-group">  <label for="phone">手机号:</label>  <div class="row">  <div class="col-sm-10">  <input type="num" id="phone" ng-model="user.phone" name="phone" class="form-control" required ng-minlength="11" ng-maxlength="11" phone>  </div>  <div class="col-sm-2">  <button class="btn btn-default" type="button" ng-disabled="register_form.phone.$invalid">发送验证码</button>  </div>  </div>  <span class="glyphicon glyphicon-ok right" ng-show="register_form.phone.$valid"></span>  </div>  <div class="alert alert-danger" ng-show="register_form.phone.$error.phone">  <strong>请注意！</strong>  该手机号已注册过，可直接登录。  </div>  <div class="alert alert-danger" ng-show="register_form.phone.$touched && !register_form.phone.$error.phone && (register_form.phone.$error.required || register_form.phone.$error.minlength || register_form.phone.$error.maxlength)">  <strong>请注意！</strong>  请输入正确的手机号。  </div>  <div class="form-group">  <label for="code">验证码:</label>  <input type="text" id="code" ng-model="user.code" class="form-control" name="code" required>  <span class="glyphicon glyphicon-ok right" ng-show="register_form.code.$valid"></span>  </div>  <!-- 在表单不合法时禁用提交按钮 -->  <button class="btn btn-block btn-primary" type="submit" ng-disabled="register_form.$invalid" ng-click="save()">提交</button>  </form>  

'use strict';
angular.module('app', [])
.controller('myCtrl', function ($scope) {  $scope.data = {};  $scope.save = function () {  alert('保存成功！')  }
})  // 判断手机号是否重复
.directive('phone', function ($q, $http) {  return {  require: 'ngModel',  link: function (scope, ele, attrs, ctrl) {  ctrl.$asyncValidators.phone = function (modelValue, viewValue) {  var d = $q.defer();  $http.get('phone.json')  .success(function (phoneList) {  if (phoneList.indexOf(parseInt(modelValue)) >= 0) {  d.reject();  } else {  d.resolve();  }  });  return d.promise;  }  }  }
})  // 验证两次输入的密码是否相同的自定义验证
.directive('pwdRepeat', function () {  return {  require: 'ngModel',  link: function (scope, ele, attrs, ctrl) {  ctrl.$validators.pwdRepeat = function (modelValue) {  // 当值为空时，通过验证，因为有required  if (ctrl.$isEmpty(modelValue)) {  return true;  }  return modelValue === scope.data._password ? true : false;  }  }  }
})  

form-group {  position: relative;
}
.right {  position: absolute;  right: 10px;  top: 34px; color: green';
}