Home Web Front-end JS Tutorial How to implement asynchronous username verification with Ajax

How to implement asynchronous username verification with Ajax

Apr 04, 2018 pm 03:58 PM
ajax asynchronous

This time I will show you how to implement asynchronous user name verification in Ajax. What are the precautions for implementing asynchronous user name verification in Ajax? Here are practical cases, let’s take a look.

Let’s take a look at the simple layout first. The rendering is as follows

ajax function:

When the user fills in When the account switches to the password box, use ajax to verify the availability of the account. The verification method is as follows: first create an XMLHTTPRequest object, then send the information that needs to be verified (user name) to the server for verification, and finally determine whether the user name is available based on the status returned by the server.

function checkAccount(){
var xmlhttp;
var name = document.getElementById("account").value;
if (window.XMLHttpRequest)
 xmlhttp=new XMLHttpRequest();
else
 xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
 
xmlhttp.open("GET","login.php?account="+name,true);
xmlhttp.send();
 
xmlhttp.onreadystatechange=function(){
 if (xmlhttp.readyState==4 && xmlhttp.status==200)
  document.getElementById("accountStatus").innerHTML=xmlhttp.responseText;
}
Copy after login

Running results

Code implementation

index.html





Ajax登陆验证



使用Ajax实现异步登陆验证

账 号:

密 码:

Copy after login

login. php

<?php
  $con = mysqli_connect("localhost","root","GDHL007","sysu");
 
  if(!empty($_GET[&#39;account&#39;])){
    $sql1 = &#39;select * from login where account = "&#39;.$_GET[&#39;account&#39;].&#39;"&#39;;
    //数据库操作
    $result1 = mysqli_query($con,$sql1);
    if(mysqli_num_rows($result1)>0)
      echo '<font style="color:#00FF00;">该用户存在</font>';
    else 
      echo '<font style="color:#FF0000;">该用户不存在</font>';
    mysqli_close($con);
  }else
    echo '<font style="color:#FF0000;">用户名不能为空</font>';
 
?>
Copy after login

I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!

Recommended reading:

Discussion and research on Ajax

How AJAX implements asynchronous refresh and partial refresh

The above is the detailed content of How to implement asynchronous username verification with Ajax. 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 solve the 403 error encountered by jQuery AJAX request How to solve the 403 error encountered by jQuery AJAX request Feb 20, 2024 am 10:07 AM

Title: Methods and code examples to resolve 403 errors in jQuery AJAX requests. The 403 error refers to a request that the server prohibits access to a resource. This error usually occurs because the request lacks permissions or is rejected by the server. When making jQueryAJAX requests, you sometimes encounter this situation. This article will introduce how to solve this problem and provide code examples. Solution: Check permissions: First ensure that the requested URL address is correct and verify that you have sufficient permissions to access the resource.

How to solve jQuery AJAX request 403 error How to solve jQuery AJAX request 403 error Feb 19, 2024 pm 05:55 PM

jQuery is a popular JavaScript library used to simplify client-side development. AJAX is a technology that sends asynchronous requests and interacts with the server without reloading the entire web page. However, when using jQuery to make AJAX requests, you sometimes encounter 403 errors. 403 errors are usually server-denied access errors, possibly due to security policy or permission issues. In this article, we will discuss how to resolve jQueryAJAX request encountering 403 error

PHP and Ajax: Building an autocomplete suggestion engine PHP and Ajax: Building an autocomplete suggestion engine Jun 02, 2024 pm 08:39 PM

Build an autocomplete suggestion engine using PHP and Ajax: Server-side script: handles Ajax requests and returns suggestions (autocomplete.php). Client script: Send Ajax request and display suggestions (autocomplete.js). Practical case: Include script in HTML page and specify search-input element identifier.

How to solve the problem of jQuery AJAX error 403? How to solve the problem of jQuery AJAX error 403? Feb 23, 2024 pm 04:27 PM

How to solve the problem of jQueryAJAX error 403? When developing web applications, jQuery is often used to send asynchronous requests. However, sometimes you may encounter error code 403 when using jQueryAJAX, indicating that access is forbidden by the server. This is usually caused by server-side security settings, but there are ways to work around it. This article will introduce how to solve the problem of jQueryAJAX error 403 and provide specific code examples. 1. to make

How to get variables from PHP method using Ajax? How to get variables from PHP method using Ajax? Mar 09, 2024 pm 05:36 PM

Using Ajax to obtain variables from PHP methods is a common scenario in web development. Through Ajax, the page can be dynamically obtained without refreshing the data. In this article, we will introduce how to use Ajax to get variables from PHP methods, and provide specific code examples. First, we need to write a PHP file to handle the Ajax request and return the required variables. Here is sample code for a simple PHP file getData.php:

Advanced Guide to Python asyncio: From Beginner to Expert Advanced Guide to Python asyncio: From Beginner to Expert Mar 04, 2024 am 09:43 AM

Concurrent and Asynchronous Programming Concurrent programming deals with multiple tasks executing simultaneously, asynchronous programming is a type of concurrent programming in which tasks do not block threads. asyncio is a library for asynchronous programming in python, which allows programs to perform I/O operations without blocking the main thread. Event loop The core of asyncio is the event loop, which monitors I/O events and schedules corresponding tasks. When a coroutine is ready, the event loop executes it until it waits for I/O operations. It then pauses the coroutine and continues executing other coroutines. Coroutines Coroutines are functions that can pause and resume execution. The asyncdef keyword is used to create coroutines. The coroutine uses the await keyword to wait for the I/O operation to complete. The following basics of asyncio

PHP vs. Ajax: Solutions for creating dynamically loaded content PHP vs. Ajax: Solutions for creating dynamically loaded content Jun 06, 2024 pm 01:12 PM

Ajax (Asynchronous JavaScript and XML) allows adding dynamic content without reloading the page. Using PHP and Ajax, you can dynamically load a product list: HTML creates a page with a container element, and the Ajax request adds the data to that element after loading it. JavaScript uses Ajax to send a request to the server through XMLHttpRequest to obtain product data in JSON format from the server. PHP uses MySQL to query product data from the database and encode it into JSON format. JavaScript parses the JSON data and displays it in the page container. Clicking the button triggers an Ajax request to load the product list.

Asynchronous and non-blocking technology in Java exception handling Asynchronous and non-blocking technology in Java exception handling May 01, 2024 pm 05:42 PM

Asynchronous and non-blocking techniques can be used to complement traditional exception handling, allowing the creation of more responsive and efficient Java applications: Asynchronous exception handling: Handling exceptions in another thread or process, allowing the main thread to continue executing, avoiding blocking. Non-blocking exception handling: involves event-driven exception handling when an I/O operation goes wrong, avoiding blocking threads and allowing the event loop to handle exceptions.

See all articles