AngularJS uses ngMessages for form validation_AngularJS

AngularJS was born in 2009, created by Misko Hevery and others, and later acquired by Google. It is an excellent front-end JS framework that has been used in many Google products. AngularJS has many features, the most core of which are: MVVM, modularization, automated two-way data binding, semantic tags, dependency injection, etc.

The module named "ngMessages" is installed through npm install angular-messages. Before using ngMessages, we might write validation like this:

<form name="userForm">
<input 
type="text" 
name="username" 
ng-model="user.username" 
ng-minlength="3" 
ng-maxlength="8"
required>
<p ng-show="userForm.username.$error.minlength">Username is too short.</p>
<p ng-show="userForm.username.$error.maxlength">Username is too long.</p>
<p ng-show="userForm.username.$error.required">Your username is required.</p>
</form>

The above lists each possible verification failure, and manually writes whether to display the error message.

With the "ngMessages" module, it can be written roughly like this:

<div class="help-block" ng-messages="userForm.name.$error" ng-if="userForm.name.$touched">
<p ng-message="minlength">用户名最小长度5</p>
<p ng-message="maxlength">用户名最大长度10</p>
<p ng-message="required">用户名必填</p>
</div>

ngMessages automatically determines which error to display for us.

Several key points when using ngMessages:

● npm install angular-messages
● Quote: angular-messages.js
● Dependency: angular.module('app',['ngMessages'])

Here is a simple Demo, file structure:

node_modules/
app.js
emailmessages.html
index.html

Installation is as follows:

npm install bootstrap
npm install angular
npm install angular-messages

==index.html

用户名

<div class="help-block" ng-messages="userForm.name.$error" ng-if="userForm.name.$touched">
<p ng-message="minlength">用户名最小长度5</p>
<p ng-message="maxlength">用户名最大长度10</p>
<p ng-message="required">用户名必填</p>
</div>


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{{userForm.name.$error}}
{{userForm.email.$error}}