<?php

header("Content-Type: application/json");
include_once("config.php");


$result = mysqli_query($mysqli, "SELECT * FROM gastos ORDER BY RAND() LIMIT 1;");
$linea = array();
while($row = mysqli_fetch_array($result))
{
    $id=$row['id'];
    $importe=$row['importe'];
    $concepto=$row['concepto'];
    $fecha=$row['fecha'];



    $linea[] = array('id'=> $id, 'importe'=> $importe, 'concepto'=> $concepto, 'fecha'=> $fecha);

}

$json_string = json_encode($linea);
echo $json_string;

$file = 'linea.json';
file_put_contents($file, $json_string);
?>

function loadDoc() {
    var xhttp = new XMLHttpRequest();

    xhttp.onreadystatechange = function() {
        if (this.readyState == 4 && this.status == 200) {
            var response = JSON.parse( this.responseText );
            consolé.log( response );
        }
    };

    xhttp.open("GET", "tu-script.php", true);
    xhttp.send();
}