search
HomeWeb Front-endJS TutorialJavaScript rewrites the asynchronous verification form into a synchronous form_javascript skills

Disadvantages of synchronous form validation

When responding to an error message, the entire page needs to be reloaded (although there is caching, the client still needs to compare whether each file has been updated through the http protocol to keep the file up to date)
After the server responds with an error, all the information previously entered by the user is lost, and the user needs to fill it in from scratch (some browsers cache this data for us)

The original intention of asynchronous verification form

Improve user experience
Minimize network requests and reduce server pressure
Let’s look at a common asynchronous form verification (verify whether the employee number exists in the background, and if it exists, it is a valid employee number)

Verify employee number

Copy code The code is as follows:

var BASE_PATH = '${rc.contextPath}';
var $workerIdInput = $('#workerIdInput');
var $workerIdError = $('#workerIdError');
//Identify whether the job number entered by the user is correct
var isWorkerIdCorrect = false;
var ERROR_WORKER_ID_IS_NULL = "Employee ID cannot be empty";
var ERROR_WORKER_ID_IS_NOT_CORRECT = "Please enter a valid employee ID";
//Display error message
function showWorkerIdError(errorMessage) {
$workerIdError.html(errorMessage);
$workerIdError.show();
}
//Hide error message
$workerIdInput.on('keydown', function() {
$workerIdError.hide();
});
//Save the last entered job number
$workerIdInput.on('focus', function() {
var workerId = $.trim($(this).val());
$(this).data('before', workerId);
});
//Verify when blurring
$workerIdInput.on('blur', function() {
var workerId = $.trim($(this).val());
//When the length is 0, the error message that the job number is empty is displayed
if (!workerId.length) {
ShowWorkerIdError(ERROR_WORKER_ID_IS_NULL);
Return false;
}
//If the data currently entered by the user is the same as the data entered last time, the background interface will not be called
//Suppose the user enters 123456, calls the background interface, and returns the result as incorrect job number
//After the user changes the input content and it is still 123456, the verification program will not access the network and directly display the error message
if (workerId == $(this).data('before')) {
If (!isWorkerIdCorrect) {
showWorkerIdError(ERROR_WORKER_ID_IS_NOT_CORRECT);
}
Return false;
}
//Call the backend interface to check whether the employee ID is correct
checkWorkerIdExists(workerId, function(data) {
isWorkerIdCorrect = data.isWorkerIdExists;
If (!isWorkerIdCorrect) {
showWorkerIdError(ERROR_WORKER_ID_IS_NOT_CORRECT);
}
});
});
function checkWorkerIdExists(workerId, callback) {
$.ajax({
URL: BASE_PATH '/forgotPwd/checkWorkerIdExists.htm',
Data: {
workerId: workerId
},
Success: callback
});
}
$workerIdForm.on('submit', function() {
//Only when the server returns true, our form can be submitted
if (!isWorkerIdCorrect) {
$workerIdInput.focus();
Return false;
}
});

After writing the above code, the verification of an input box is basically completed.

I think there are still areas that affect user experience
The carriage return operation is not supported yet, oh my god, even carriage return must be able to submit the form
If the user's Internet speed is slow, there will be no response when clicking the submit button, because isWorkerIdCorrect is false, and it will be true only if the server verification is successful

The following is the modified code:

Copy code The code is as follows:

var BASE_PATH = '${rc.contextPath}';
var $workerIdInput = $('#workerIdInput');
var $workerIdError = $('#workerIdError');
//Identify whether the job number entered by the user is correct
var isWorkerIdCorrect = false;
//Identify whether the background verification of employee ID has been completed (true: verification is in progress, false: verification has not started or has ended)
var isWorkerIdLoading = false;
//Identify whether the user has submitted the form
var isSubmit = false;
var ERROR_WORKER_ID_IS_NULL = "Employee ID cannot be empty";
var ERROR_WORKER_ID_IS_NOT_CORRECT = "Please enter a valid employee ID";
//Display error message
function showWorkerIdError(errorMessage) {
$workerIdError.html(errorMessage);
$workerIdError.show();
}
//Hide error message
$workerIdInput.on('keydown', function() {
$workerIdError.hide();
});
//Save the last entered job number
$workerIdInput.on('focus', function() {
var workerId = $.trim($(this).val());
$(this).data('before', workerId);
});
//Verify when blurring
$workerIdInput.on('blur', function() {
var workerId = $.trim($(this).val());
//When the length is 0, the error message that the job number is empty is displayed
if (!workerId.length) {
ShowWorkerIdError(ERROR_WORKER_ID_IS_NULL);
Return false;
}
//If the data currently entered by the user is the same as the data entered last time, the background interface will not be called
//Suppose the user enters 123456, calls the background interface, and returns the result as incorrect job number
//After the user changes the input content and it is still 123456, the verification program will not access the network and directly display the error message
if (workerId == $(this).data('before')) {
If (!isWorkerIdCorrect) {
showWorkerIdError(ERROR_WORKER_ID_IS_NOT_CORRECT);
}
Return false;
}
//Call the backend interface to check whether the employee ID exists
checkWorkerIdExists(workerId, function(data) {
isWorkerIdCorrect = data.isWorkerIdExists;
If (!isWorkerIdCorrect) {
showWorkerIdError(ERROR_WORKER_ID_IS_NOT_CORRECT);
}
});
});
function checkWorkerIdExists(workerId, callback) {
$.ajax({
URL: BASE_PATH '/forgotPwd/checkWorkerIdExists.htm',
Data: {
workerId: workerId
},
beforeSend: function() {
//Before sending the request, the ID is being verified
​​​isWorkerIdLoading = true;
},
Success: callback,
Complete: function() {
//After finishing, close the logo
​​​isWorkerIdLoading = false;
//During the background data verification process, if the user submits the form, it will be automatically submitted here
If (isSubmit) {
          $workerIdForm.submit();
}
}
});
}
//Press enter to submit the form
$workerIdInput.on('keypress', function(e) {
if (e.which === 13) {
$(this).blur();
$workerIdForm.submit();
}
});
$workerIdForm.on('submit', function() {
//If the employee number is being verified in the background, it indicates that the user has submitted the form
if (isWorkerIdLoading) {
isSubmit = true;
Return false;
}
if (!isWorkerIdCorrect) {
$workerIdInput.focus();
Return false;
}
});

Final effect, the two input boxes in the picture are both asynchronously verified, but the effect looks the same as synchronous.
The picture uses gprs network to simulate the situation of slow network speed

Rendering

Statement
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
es6数组怎么去掉重复并且重新排序es6数组怎么去掉重复并且重新排序May 05, 2022 pm 07:08 PM

去掉重复并排序的方法:1、使用“Array.from(new Set(arr))”或者“[…new Set(arr)]”语句,去掉数组中的重复元素,返回去重后的新数组;2、利用sort()对去重数组进行排序,语法“去重数组.sort()”。

JavaScript的Symbol类型、隐藏属性及全局注册表详解JavaScript的Symbol类型、隐藏属性及全局注册表详解Jun 02, 2022 am 11:50 AM

本篇文章给大家带来了关于JavaScript的相关知识,其中主要介绍了关于Symbol类型、隐藏属性及全局注册表的相关问题,包括了Symbol类型的描述、Symbol不会隐式转字符串等问题,下面一起来看一下,希望对大家有帮助。

原来利用纯CSS也能实现文字轮播与图片轮播!原来利用纯CSS也能实现文字轮播与图片轮播!Jun 10, 2022 pm 01:00 PM

怎么制作文字轮播与图片轮播?大家第一想到的是不是利用js,其实利用纯CSS也能实现文字轮播与图片轮播,下面来看看实现方法,希望对大家有所帮助!

JavaScript对象的构造函数和new操作符(实例详解)JavaScript对象的构造函数和new操作符(实例详解)May 10, 2022 pm 06:16 PM

本篇文章给大家带来了关于JavaScript的相关知识,其中主要介绍了关于对象的构造函数和new操作符,构造函数是所有对象的成员方法中,最早被调用的那个,下面一起来看一下吧,希望对大家有帮助。

JavaScript面向对象详细解析之属性描述符JavaScript面向对象详细解析之属性描述符May 27, 2022 pm 05:29 PM

本篇文章给大家带来了关于JavaScript的相关知识,其中主要介绍了关于面向对象的相关问题,包括了属性描述符、数据描述符、存取描述符等等内容,下面一起来看一下,希望对大家有帮助。

javascript怎么移除元素点击事件javascript怎么移除元素点击事件Apr 11, 2022 pm 04:51 PM

方法:1、利用“点击元素对象.unbind("click");”方法,该方法可以移除被选元素的事件处理程序;2、利用“点击元素对象.off("click");”方法,该方法可以移除通过on()方法添加的事件处理程序。

整理总结JavaScript常见的BOM操作整理总结JavaScript常见的BOM操作Jun 01, 2022 am 11:43 AM

本篇文章给大家带来了关于JavaScript的相关知识,其中主要介绍了关于BOM操作的相关问题,包括了window对象的常见事件、JavaScript执行机制等等相关内容,下面一起来看一下,希望对大家有帮助。

foreach是es6里的吗foreach是es6里的吗May 05, 2022 pm 05:59 PM

foreach不是es6的方法。foreach是es3中一个遍历数组的方法,可以调用数组的每个元素,并将元素传给回调函数进行处理,语法“array.forEach(function(当前元素,索引,数组){...})”;该方法不处理空数组。

See all articles

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

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)
2 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
Repo: How To Revive Teammates
4 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
Hello Kitty Island Adventure: How To Get Giant Seeds
3 weeks agoBy尊渡假赌尊渡假赌尊渡假赌

Hot Tools

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

MantisBT

MantisBT

Mantis is an easy-to-deploy web-based defect tracking tool designed to aid in product defect tracking. It requires PHP, MySQL and a web server. Check out our demo and hosting services.

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

DVWA

DVWA

Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software