search
HomeBackend DevelopmentPHP Tutorialjavascript - How to get background data through ajax based on drop-down menu selection without refreshing the page

I want to use a set of drop-down menus, and then when selecting one of them, filter out the list that meets the conditions based on the selected list title and display it on the page below. How can I implement the code?

Reply content:

I want to use a set of drop-down menus, and then when selecting one of them, filter out the list that meets the conditions based on the selected list title and display it on the page below. How can I implement the code?

<code>$('select').change(function(){//监控select的change事件
    var dom = document.getElementById('id'),
    data = dom.options[dom.selectedIndex].value;//选中的option的value;

    ajax({});
    
});</code>

There are roughly the following steps:

    Get the value of the
  1. selected

    drop-down menu (ID/title, usually the ID will be obtained, and go to the background to obtain the corresponding data from the database based on this ID)

  2. Send to
  3. Backend

  4. The backend takes the value of the parameters sent by the frontend, queries the database, and then assembles it into the format type you want and returns it to the frontend
  5. The front-end implements html operations (content update)
  6. The code is implemented as follows (using jQuery)
  7. <code><script type="text/javascript">
        $("select").change(function() {
            var title = $(this).text();  // 1、获取选择下拉框的标题
            //var id  = $(this).val();  获取选中的ID值
            var url   = "";  //这里填写后端的url 
            $.ajax({   //2、发送给后端
                url: url, 
                type: 'POST',  //设置发送的方式 这里假设为POST
                dataType: 'html',  //返回的数据类型
                data: {title: title},  //把选中的标题发给后端
                success:function(data) {
                    // 4、这里写成功后更新页面的操作
                }
            })
        });
    </script></code>
    <code><?php $title = $_POST['title']; //接收参数  选中的ID或者标题
    
    //3、根据这个标题或者ID 去数据库查询匹配到的相关的内容 然后根据需求组装成html格式
    
    echo $html;  //返回给前端
    exit;</code></code>
It’s roughly divided into three steps:

<code>1、ajax请求后端接口,接口返回数据。(一般返回json)
2、ajax在回调函数里面,解析数据。
3、把数据写到页面,看你情况用html还是append</code>

Such a broad question; first understand the following "js template";

<code>$("select").onchange(function(){
    console.log($(this).val());//这里的this.val 就是当前选中的option的val 根据这个val 进行逻辑判断
})</code>
It is recommended to write a function in the log and pass the value to perform logical operations

The answers above are all very good, it’s nothing more than the onchange event of javascript

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
Explain how load balancing affects session management and how to address it.Explain how load balancing affects session management and how to address it.Apr 29, 2025 am 12:42 AM

Load balancing affects session management, but can be resolved with session replication, session stickiness, and centralized session storage. 1. Session Replication Copy session data between servers. 2. Session stickiness directs user requests to the same server. 3. Centralized session storage uses independent servers such as Redis to store session data to ensure data sharing.

Explain the concept of session locking.Explain the concept of session locking.Apr 29, 2025 am 12:39 AM

Sessionlockingisatechniqueusedtoensureauser'ssessionremainsexclusivetooneuseratatime.Itiscrucialforpreventingdatacorruptionandsecuritybreachesinmulti-userapplications.Sessionlockingisimplementedusingserver-sidelockingmechanisms,suchasReentrantLockinJ

Are there any alternatives to PHP sessions?Are there any alternatives to PHP sessions?Apr 29, 2025 am 12:36 AM

Alternatives to PHP sessions include Cookies, Token-based Authentication, Database-based Sessions, and Redis/Memcached. 1.Cookies manage sessions by storing data on the client, which is simple but low in security. 2.Token-based Authentication uses tokens to verify users, which is highly secure but requires additional logic. 3.Database-basedSessions stores data in the database, which has good scalability but may affect performance. 4. Redis/Memcached uses distributed cache to improve performance and scalability, but requires additional matching

Define the term 'session hijacking' in the context of PHP.Define the term 'session hijacking' in the context of PHP.Apr 29, 2025 am 12:33 AM

Sessionhijacking refers to an attacker impersonating a user by obtaining the user's sessionID. Prevention methods include: 1) encrypting communication using HTTPS; 2) verifying the source of the sessionID; 3) using a secure sessionID generation algorithm; 4) regularly updating the sessionID.

What is the full form of PHP?What is the full form of PHP?Apr 28, 2025 pm 04:58 PM

The article discusses PHP, detailing its full form, main uses in web development, comparison with Python and Java, and its ease of learning for beginners.

How does PHP handle form data?How does PHP handle form data?Apr 28, 2025 pm 04:57 PM

PHP handles form data using $\_POST and $\_GET superglobals, with security ensured through validation, sanitization, and secure database interactions.

What is the difference between PHP and ASP.NET?What is the difference between PHP and ASP.NET?Apr 28, 2025 pm 04:56 PM

The article compares PHP and ASP.NET, focusing on their suitability for large-scale web applications, performance differences, and security features. Both are viable for large projects, but PHP is open-source and platform-independent, while ASP.NET,

Is PHP a case-sensitive language?Is PHP a case-sensitive language?Apr 28, 2025 pm 04:55 PM

PHP's case sensitivity varies: functions are insensitive, while variables and classes are sensitive. Best practices include consistent naming and using case-insensitive functions for comparisons.

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

Video Face Swap

Video Face Swap

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

Hot Tools

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

WebStorm Mac version

WebStorm Mac version

Useful JavaScript development tools

SAP NetWeaver Server Adapter for Eclipse

SAP NetWeaver Server Adapter for Eclipse

Integrate Eclipse with SAP NetWeaver application server.

Safe Exam Browser

Safe Exam Browser

Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.

mPDF

mPDF

mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),