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. The following is a sample code for a simple PHP file getData.php:

<?php
    // 獲取傳遞進(jìn)來的參數(shù)
    $param = $_POST['param'];

    // 執(zhí)行一些操作，比如從數(shù)據(jù)庫中獲取數(shù)據(jù)
    $result = fetchDataFromDatabase($param);

    // 返回結(jié)果
    echo json_encode($result);

    // 從數(shù)據(jù)庫獲取數(shù)據(jù)的函數(shù)示例
    function fetchDataFromDatabase($param) {
        // 連接數(shù)據(jù)庫
        $conn = new mysqli('localhost', 'username', 'password', 'database');

        // 執(zhí)行查詢
        $query = "SELECT * FROM table WHERE column = '$param'";
        $result = $conn->query($query);

        // 處理查詢結(jié)果
        $data = array();
        while($row = $result->fetch_assoc()) {
            $data[] = $row;
        }

        // 關(guān)閉數(shù)據(jù)庫連接
        $conn->close();

        return $data;
    }
?>

Next, we need to write JavaScript code in the front-end page to send an Ajax request and obtain the variables in the PHP method . The following is a simple sample code:

// 創(chuàng)建一個(gè)XMLHttpRequest對(duì)象
var xhr = new XMLHttpRequest();

// 設(shè)置Ajax請(qǐng)求的方法、URL和是否異步
xhr.open('POST', 'getData.php', true);

// 設(shè)置請(qǐng)求頭信息
xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');

// 監(jiān)聽Ajax請(qǐng)求的狀態(tài)變化
xhr.onreadystatechange = function() {
    if(xhr.readyState == 4 && xhr.status == 200) {
        // 獲取PHP返回的數(shù)據(jù)
        var data = JSON.parse(xhr.responseText);

        // 處理獲取到的數(shù)據(jù)
        processData(data);
    }
};

// 發(fā)送Ajax請(qǐng)求
xhr.send('param=value');

In the above code, an XMLHttpRequest object is first created, and the request method, URL and whether it is asynchronous are set. Then in the status change event of the request, determine whether the request is successful and obtain the returned data, and finally process the obtained data. It should be noted that parameters need to be passed when sending a request, and parameters can be passed through the xhr.send() method.

In summary, through the above code examples, you can use Ajax to obtain variables from PHP methods. The front-end page sends an Ajax request to the back-end PHP file, and the back-end PHP file performs corresponding operations and returns data. The front-end page then processes the returned data, achieving the effect of obtaining data without refreshing the page.

The above is the detailed content of How to get variables from PHP method using Ajax?. For more information, please follow other related articles on the PHP Chinese website!