search
HomeBackend DevelopmentPHP TutorialAJAX Operation Guide in PHP

With the development of Internet technology, front-end web development has become more and more important. In web development, the emergence of JavaScript has accelerated the implementation of many interactivity and dynamics. However, JavaScript is not a back-end language and cannot interact directly with databases or file systems. Therefore, in order to achieve more efficient web development, AJAX technology was introduced.

AJAX is the abbreviation of "Asynchronous JavaScript and XML". It uses JavaScript, XML, HTML and CSS technologies to implement asynchronous data transmission and can interact with the server without refreshing the page. In PHP, AJAX technology is increasingly used. This article will provide a detailed explanation of AJAX operations in PHP.

1. Interaction without refreshing the page

In web applications, user operations may need to obtain data from the server, such as search results, asynchronous requests, form submissions, etc. Taking form submission as an example, the simplest way is to set a submit button in the

tag of the page:
<form action="submit.php" method="post">
    ...
    <input type="submit" value="提交">
</form>

After the user submits the form, the page will be reloaded and the fields in the form will be changed. The data is sent to the server so that the user can get the response returned from the server. However, this method requires the page to be reloaded, causing unnecessary delays and affecting the user experience.

In order to avoid this situation, we can use AJAX technology to implement form submission without refreshing the page. This can be achieved in the following ways:

var xhr = new XMLHttpRequest();
xhr.open("POST", "submit.php", true);
xhr.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xhr.onreadystatechange = function() {
    if(xhr.readyState === 4 && xhr.status === 200) {
        document.getElementById("result").innerHTML = xhr.responseText;
    }
};
var formData = new FormData(document.getElementById("form"));
xhr.send(formData);

The above code first creates the XMLHttpRequest object xhr , and then use the open method to set the request method (POST), URL (submit.php) and asynchronous transmission (true). Next, use the setRequestHeader method to set the Content-type header information. In the onreadystatechange callback function, we can determine the status of the request and the status code of the response to ensure that the request returns successfully. Finally, use the FormData object to obtain the form data and send the request through the send method.

2. Use jQuery to implement AJAX

jQuery is a popular JavaScript library that provides a series of convenient functions and tools to simplify AJAX operations. With jQuery, we can easily implement AJAX requests. The following is a sample code for implementing AJAX using jQuery:

$("#form").on("submit", function(event) {
    event.preventDefault();
    $.ajax({
        url: "submit.php",
        type: "POST",
        data: new FormData(this),
        processData: false,
        contentType: false,
        success: function(data) {
            $("#result").html(data);
        },
        error: function() {
            alert("请求失败!");
        }
    });
});

The above code will use jQuery's ajax method to perform an AJAX request. Before submitting the form, we use event.preventDefault() to prevent the default form submission event so as not to refresh the page. Next, set the url attribute to submit.php, the type attribute to POST, use the FormData object to obtain the form data, and set the processData and contentType attributes to false to ensure that the form data is not processed. When the request is successful, we can perform corresponding operations in the success callback function. When the request fails, we can handle it accordingly in the error callback function.

3. AJAX access to JSON data returned by PHP

When an AJAX request is made to PHP, PHP can return various data types, such as HTML, XML, JSON and ordinary text. In PHP, using JSON for data exchange is becoming more and more popular, so returning JSON data in AJAX requests has become an important issue. The following is a simple PHP program that shows how to return data from the database in JSON format:

<?php
    $db = new PDO("mysql:host=localhost;dbname=test", "root", "password");
    $query = $db->prepare("SELECT * FROM users");
    $query->execute();
    $result = $query->fetchAll(PDO::FETCH_ASSOC);
    echo json_encode($result);
?>

The above code uses the PDO library to connect to the database and get all the data from the users table. Through the json_encode function, we convert the data into JSON format and output it to the page. Then, the data can be obtained and processed in the AJAX request:

$.ajax({
    url: "get_data.php",
    type: "GET",
    dataType: "json",
    success: function(data) {
        console.log(data);
    }
});

The above code uses jQuery's ajax method to obtain the data, and sets the dataType attribute to json. When the request is successful, the data parameter will contain data in JSON format, and we can use the console.log method to output the data. Of course, we can also parse the data and perform corresponding operations.

Summary

This article provides a detailed explanation of AJAX operations in PHP. The use of AJAX technology can not only improve the efficiency and user experience of Web applications, but also enable more flexible and convenient data exchange. AJAX has become an indispensable web development technology. For PHP developers, mastering AJAX technology can achieve more efficient and dynamic web applications.

The above is the detailed content of AJAX Operation Guide in PHP. For more information, please follow other related articles on the PHP Chinese website!

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
php怎么把负数转为正整数php怎么把负数转为正整数Apr 19, 2022 pm 08:59 PM

php把负数转为正整数的方法:1、使用abs()函数将负数转为正数,使用intval()函数对正数取整,转为正整数,语法“intval(abs($number))”;2、利用“~”位运算符将负数取反加一,语法“~$number + 1”。

php怎么实现几秒后执行一个函数php怎么实现几秒后执行一个函数Apr 24, 2022 pm 01:12 PM

实现方法:1、使用“sleep(延迟秒数)”语句,可延迟执行函数若干秒;2、使用“time_nanosleep(延迟秒数,延迟纳秒数)”语句,可延迟执行函数若干秒和纳秒;3、使用“time_sleep_until(time()+7)”语句。

php怎么除以100保留两位小数php怎么除以100保留两位小数Apr 22, 2022 pm 06:23 PM

php除以100保留两位小数的方法:1、利用“/”运算符进行除法运算,语法“数值 / 100”;2、使用“number_format(除法结果, 2)”或“sprintf("%.2f",除法结果)”语句进行四舍五入的处理值,并保留两位小数。

php怎么根据年月日判断是一年的第几天php怎么根据年月日判断是一年的第几天Apr 22, 2022 pm 05:02 PM

判断方法:1、使用“strtotime("年-月-日")”语句将给定的年月日转换为时间戳格式;2、用“date("z",时间戳)+1”语句计算指定时间戳是一年的第几天。date()返回的天数是从0开始计算的,因此真实天数需要在此基础上加1。

php怎么判断有没有小数点php怎么判断有没有小数点Apr 20, 2022 pm 08:12 PM

php判断有没有小数点的方法:1、使用“strpos(数字字符串,'.')”语法,如果返回小数点在字符串中第一次出现的位置,则有小数点;2、使用“strrpos(数字字符串,'.')”语句,如果返回小数点在字符串中最后一次出现的位置,则有。

php怎么替换nbsp空格符php怎么替换nbsp空格符Apr 24, 2022 pm 02:55 PM

方法:1、用“str_replace("&nbsp;","其他字符",$str)”语句,可将nbsp符替换为其他字符;2、用“preg_replace("/(\s|\&nbsp\;||\xc2\xa0)/","其他字符",$str)”语句。

php怎么设置implode没有分隔符php怎么设置implode没有分隔符Apr 18, 2022 pm 05:39 PM

在PHP中,可以利用implode()函数的第一个参数来设置没有分隔符,该函数的第一个参数用于规定数组元素之间放置的内容,默认是空字符串,也可将第一个参数设置为空,语法为“implode(数组)”或者“implode("",数组)”。

php字符串有没有下标php字符串有没有下标Apr 24, 2022 am 11:49 AM

php字符串有下标。在PHP中,下标不仅可以应用于数组和对象,还可应用于字符串,利用字符串的下标和中括号“[]”可以访问指定索引位置的字符,并对该字符进行读写,语法“字符串名[下标值]”;字符串的下标值(索引值)只能是整数类型,起始值为0。

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

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

Atom editor mac version download

Atom editor mac version download

The most popular open source editor

Dreamweaver Mac version

Dreamweaver Mac version

Visual web development tools

PhpStorm Mac version

PhpStorm Mac version

The latest (2018.2.1) professional PHP integrated development tool

SecLists

SecLists

SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.