Home Web Front-end JS Tutorial AngularJs form validation methods

AngularJs form validation methods

Oct 19, 2017 am 09:25 AM
angularjs javascript method

Anjularjs Form Validation

It is very important to be able to give real-time visual feedback based on what the user enters in the form. In the context of human-to-human communication, the feedback given by form validation is as important as obtaining correct input.

Form validation can not only provide useful feedback to users, but also protect our web applications from being damaged by malicious or incorrect input. We have to do our best to protect the backend on the web frontend.

AngularJS can combine the HTML5 form validation function with its own validation instructions, and it is very convenient. AngularJS provides many form validation instructions.


<form name="form" novalidate>
    <label name="email">Your email</label>
    <input type="email" name="email" ng-model="email" placeholder="Email Address"/></form>
Copy after login

To use form validation, first make sure the form has a name attribute like the example above.

All input fields can be subject to basic validation, such as maximum and minimum length, etc. These capabilities are provided by new HTML5 form attributes.

If you want to block the browser’s default validation behavior for the form, you can add the novalidate tag to the form element

1. Required

To verify whether a form input has been filled in, just add the HTML5 tag required on the input field element:

 Note: The required attribute applies to the following types :text, search, url, telephone, email, password, date pickers, number, checkbox, radio and file


<input type="text" required />
Copy after login

 2. Minimum length ng -minleng="{number}"

To verify whether the text length entered in the form is greater than a certain minimum value, use the AngularJS directive ng-minleng="{number}"

# on the input field


##

<input type="text" ng-minlength="5" />
Copy after login

 3. Maximum length ng-maxlength="{number}"

Verify whether the text length entered in the form is less than or equal to a certain maximum length value, use the AngularJS directive ng-maxlength="{number}"


<input type="text" ng-maxlength="20" />
Copy after login

on the input field 4. Pattern matching ng-pattern="/PATTERN/"

Use ng-pattern="/PATTERN/" to ensure that the input matches the specified regular expression:


<input type="text" ng-pattern="[a-zA-Z]" />
Copy after login

 5 . Email

To verify whether the input content is an email, just set the input type to email as follows:


<input type="email" name="email" ng-model="user.email" />
Copy after login

 6. Numbers

Verify whether the input content is a number and set the input type to number:


<input type="number" name="age" ng-model="user.age" />
Copy after login

7 . URL

Verify whether the input content is a URL, set the input type to url:


<input type="url" name="homepage" ng-model="user.facebook_url" />
Copy after login

Control variables in the form

The properties of the form can be accessed in the $scope object to which they belong, and we can access the $scope object, so JavaScript can indirectly access the form properties in the DOM. With the help of these properties, we can make real-time (like everything else in AngularJS) responses to the form. These properties include the following. (Note that these properties can be accessed using the format below.)

formName.inputFieldName.property


■Unmodified form

This is a Boolean property, Used to determine whether the user has modified the form. If it has not been modified, the value is true, if it has been modified, the value is false


formName.inputFieldName.$pristine
Copy after login

■Modified form

As long as the user has modified the form, regardless of whether the input is After verification, the value will return true


formName.inputFieldName.$dirty
Copy after login

■Legal form

This Boolean attribute is used to determine whether the content of the form is legal. If the current form content is legal, the value of the following attribute is true:


formName.inputFieldName.$valid
Copy after login

■ Illegal form

This Boolean attribute is used to determine the form Whether the content is illegal. If the current form content is illegal, the value of the following attribute is true:


formName.inputFieldName.$invalid
Copy after login

■ Error

This is another very useful feature provided by AngularJS Properties: $error object. It contains all validations for the current form, as well as information on whether they are valid or not. Use the following syntax to access this property:


formName.inputfieldName.$error
Copy after login

$parsers

When the user interacts with the controller, and the ngModelController When the $setViewValue() method is called, the functions in the $parsers array will be called one by one in a pipeline. After the first $parse is called, the execution result will be passed to the second $parse, and so on

These functions can convert the input value, or set the validity of the form through the $setValidity() function .

Using the $parsers array is one of the ways to implement custom validation.

  例如,假设我们想要确保输入值在某两个数值之间,可以在 $parsers 数组中入栈一个新的函数,这个函数会在验证链中被调用。

  每个 $parser 返回的值都会被传入下一个 $parser 中。当不希望数据模型发生更新时返回undefined 。

html


<!DOCTYPE html><html ng-app="myApp"><head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <title>表单测试</title>
    <link rel="stylesheet" href="">
    <script type="text/javascript" src="angular.1.2.13.js"></script></head><body>
    <p ng-controller="TestController">
        <form name="testForm">
            <input type="number" name="inputs" ng-test ng-model="obj.number">
            <span ng-show="testForm.inputs.$error.test">good</span>
            <span ng-hide="testForm.inputs.$error.test">bad</span>
            <p>{{ testForm.inputs.$valid }}</p>
            <p>{{ testForm.inputs.$invalid }}</p>
            <p>{{ obj.number }}</p>
        </form>
    </p>
    <script type="text/javascript" src="test5app.js"></script></body></html>
Copy after login

javascript ( test5app.js )


angular.module(&#39;myApp&#39;, []).controller(&#39;TestController&#39;, function($scope) {
    $scope.obj = {
        number: 34
    }
}).directive(&#39;ngTest&#39;, function() {    
return {
        require: &#39;?ngModel&#39;,
        restrict: &#39;AE&#39;,
        link: function($scope, iElm, iAttrs, ngModel) {            
        if (!ngModel) return;
            ngModel.$parsers.push(function(viewValue) {                
            var num = parseInt(viewValue);                
            if (num >= 0 && num < 99) {
                    ngModel.$setValidity(&#39;test&#39;, true);                    
                    return viewValue
                } else {
                    ngModel.$setValidity(&#39;test&#39;, false);                    
                    return undefined
                }
            })
        }
    }
});
Copy after login

The above is the detailed content of AngularJs form validation methods. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

How to delete WeChat friends? How to delete WeChat friends How to delete WeChat friends? How to delete WeChat friends Mar 04, 2024 am 11:10 AM

WeChat is one of the mainstream chat tools. We can meet new friends, contact old friends and maintain the friendship between friends through WeChat. Just as there is no such thing as a banquet that never ends, disagreements will inevitably occur when people get along with each other. When a person extremely affects your mood, or you find that your views are inconsistent when you get along, and you can no longer communicate, then we may need to delete WeChat friends. How to delete WeChat friends? The first step to delete WeChat friends: tap [Address Book] on the main WeChat interface; the second step: click on the friend you want to delete and enter [Details]; the third step: click [...] in the upper right corner; Step 4: Click [Delete] below; Step 5: After understanding the page prompts, click [Delete Contact]; Warm

How to recover deleted contacts on WeChat (simple tutorial tells you how to recover deleted contacts) How to recover deleted contacts on WeChat (simple tutorial tells you how to recover deleted contacts) May 01, 2024 pm 12:01 PM

Unfortunately, people often delete certain contacts accidentally for some reasons. WeChat is a widely used social software. To help users solve this problem, this article will introduce how to retrieve deleted contacts in a simple way. 1. Understand the WeChat contact deletion mechanism. This provides us with the possibility to retrieve deleted contacts. The contact deletion mechanism in WeChat removes them from the address book, but does not delete them completely. 2. Use WeChat’s built-in “Contact Book Recovery” function. WeChat provides “Contact Book Recovery” to save time and energy. Users can quickly retrieve previously deleted contacts through this function. 3. Enter the WeChat settings page and click the lower right corner, open the WeChat application "Me" and click the settings icon in the upper right corner to enter the settings page.

How to write a novel in the Tomato Free Novel app. Share the tutorial on how to write a novel in Tomato Novel. How to write a novel in the Tomato Free Novel app. Share the tutorial on how to write a novel in Tomato Novel. Mar 28, 2024 pm 12:50 PM

Tomato Novel is a very popular novel reading software. We often have new novels and comics to read in Tomato Novel. Every novel and comic is very interesting. Many friends also want to write novels. Earn pocket money and edit the content of the novel you want to write into text. So how do we write the novel in it? My friends don’t know, so let’s go to this site together. Let’s take some time to look at an introduction to how to write a novel. Share the Tomato novel tutorial on how to write a novel. 1. First open the Tomato free novel app on your mobile phone and click on Personal Center - Writer Center. 2. Jump to the Tomato Writer Assistant page - click on Create a new book at the end of the novel.

How to enter bios on Colorful motherboard? Teach you two methods How to enter bios on Colorful motherboard? Teach you two methods Mar 13, 2024 pm 06:01 PM

Colorful motherboards enjoy high popularity and market share in the Chinese domestic market, but some users of Colorful motherboards still don’t know how to enter the bios for settings? In response to this situation, the editor has specially brought you two methods to enter the colorful motherboard bios. Come and try it! Method 1: Use the U disk startup shortcut key to directly enter the U disk installation system. The shortcut key for the Colorful motherboard to start the U disk with one click is ESC or F11. First, use Black Shark Installation Master to create a Black Shark U disk boot disk, and then turn on the computer. When you see the startup screen, continuously press the ESC or F11 key on the keyboard to enter a window for sequential selection of startup items. Move the cursor to the place where "USB" is displayed, and then

The secret of hatching mobile dragon eggs is revealed (step by step to teach you how to successfully hatch mobile dragon eggs) The secret of hatching mobile dragon eggs is revealed (step by step to teach you how to successfully hatch mobile dragon eggs) May 04, 2024 pm 06:01 PM

Mobile games have become an integral part of people's lives with the development of technology. It has attracted the attention of many players with its cute dragon egg image and interesting hatching process, and one of the games that has attracted much attention is the mobile version of Dragon Egg. To help players better cultivate and grow their own dragons in the game, this article will introduce to you how to hatch dragon eggs in the mobile version. 1. Choose the appropriate type of dragon egg. Players need to carefully choose the type of dragon egg that they like and suit themselves, based on the different types of dragon egg attributes and abilities provided in the game. 2. Upgrade the level of the incubation machine. Players need to improve the level of the incubation machine by completing tasks and collecting props. The level of the incubation machine determines the hatching speed and hatching success rate. 3. Collect the resources required for hatching. Players need to be in the game

Summary of methods to obtain administrator rights in Win11 Summary of methods to obtain administrator rights in Win11 Mar 09, 2024 am 08:45 AM

A summary of how to obtain Win11 administrator rights. In the Windows 11 operating system, administrator rights are one of the very important permissions that allow users to perform various operations on the system. Sometimes, we may need to obtain administrator rights to complete some operations, such as installing software, modifying system settings, etc. The following summarizes some methods for obtaining Win11 administrator rights, I hope it can help you. 1. Use shortcut keys. In Windows 11 system, you can quickly open the command prompt through shortcut keys.

How to set font size on mobile phone (easily adjust font size on mobile phone) How to set font size on mobile phone (easily adjust font size on mobile phone) May 07, 2024 pm 03:34 PM

Setting font size has become an important personalization requirement as mobile phones become an important tool in people's daily lives. In order to meet the needs of different users, this article will introduce how to improve the mobile phone use experience and adjust the font size of the mobile phone through simple operations. Why do you need to adjust the font size of your mobile phone - Adjusting the font size can make the text clearer and easier to read - Suitable for the reading needs of users of different ages - Convenient for users with poor vision to use the font size setting function of the mobile phone system - How to enter the system settings interface - In Find and enter the "Display" option in the settings interface - find the "Font Size" option and adjust it. Adjust the font size with a third-party application - download and install an application that supports font size adjustment - open the application and enter the relevant settings interface - according to the individual

Detailed explanation of Oracle version query method Detailed explanation of Oracle version query method Mar 07, 2024 pm 09:21 PM

Detailed explanation of Oracle version query method Oracle is one of the most popular relational database management systems in the world. It provides rich functions and powerful performance and is widely used in enterprises. In the process of database management and development, it is very important to understand the version of the Oracle database. This article will introduce in detail how to query the version information of the Oracle database and give specific code examples. Query the database version of the SQL statement in the Oracle database by executing a simple SQL statement

See all articles