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';
}