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May
Asked: 2020-09-19 07:46:45 +0800 CST 2020-09-19 07:46:45 +0800 CST

How to send the data that stores a variable in jQuery through AJAX to a PHP and save in the database with MySQLi?

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I am making a counter of how many online users are seeing a question. Example: Pedro and Juan and one more person are seeing this question. The variable user_onlinestores the names of online users. I use because through AJAX I want to refresh online users.

var user_online = ["Pedro", "Juan", "Carlos"];


My question is how do I, when pressing a button on the page, send the value of this variable, collecting the values ​​in PHP and saving it in the database using , following this structure:

 id    User_Online
----  ---------------------
 1     Pedro, Juan, Carlos
php

1 Answers

  1. Best Answer

    To send an array from JavaScript, using jQuery AJAX, receive it in PHP and save it in MySQL, the following steps are used:

    1. Suppose an HTML like this:

    <html>
  <head>
    <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/3.1.0/jquery.min.js"></script>
    <script type="text/javascript" src="grabarbd.js"></script>
  </head>

  <body>
    <input type="button" value="Grabar en BD" onclick="grabarBD();">
  </body>
</html>

    2. In grabarbd.js, send the array by POST

    function grabarBD() {
    // Datos como tiene el usuario
    var user_online = ["Pedro", "Juan", "Carlos"];
    var id = 1; //el id con el que quieras guardar

    // Convertir a objeto
    var data = {};
    data.user_online = user_online;
    data.id = id;

    // enviar por POST mediante AJAX
    var url = 'grabarbd.php';   //este es el PHP al que se llama por AJAX
    $.ajax({
        method: 'POST',
        url: url,
        data: data,   //acá están todos los parámetros (valores a enviar) del POST
        success: function(response){
            // Se ejecuta al finalizar
            //   mostrar si está OK en consola
            console.log(response);
        }
    });
}

    3. In grabarbd.php, the value is received and recorded in the base

    if (isset($_POST['id']) && !empty($_POST['id']) && isset($_POST['user_online']) && !empty($_POST['user_online'])) {
    // Datos recibidos
    $id = $_POST['id'];
    $user_online = implode(', ', $_POST['user_online']);

    //Datos de conexión a la base
    $host = "localhost";
    $usuario = "usuario";
    $clave = "clave";
    $basedatos = "NombreBaseDeDatos";
    $tabla = "NombreDeTabla";

    // Conectar a la base
    //  la variable $myslqi contendrá el objeto con la conexión
    $mysqli = mysqli_connect($host, $usuario, $clave, $basedatos);
    if (mysqli_connect_errno($mysqli)) {
        die( "Error al conectar a MySQL: " . mysqli_connect_error() );
    }

    // insert en la base
    $sentencia = $mysqli->prepare("INSERT INTO $tabla (id, User_Online) VALUES (?, ?)");
    $sentencia->bind_param("is", $id, $user_online );
    $sentencia->execute();

    // Cerrar la conexión
    $sentencia = null;
    $mysqli = null;

    // Devolver una respuesta a JavaScript
    echo "Se grabó el id = $id, con User_Online = $user_online";
}

    Note: This is an example showing basic functionality. The treatment of possible errors must be added.

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