<?php

class BMI {
    public $height;
    public $weight;
    public $bmi;
    public $date;
}

//Set MIME type
header('Content-type: application/json');

//Print XML
$height = $_GET['height'];
$weight = $_GET['weight'];
$bmi = $weight / ($height * $height);

$myBmiThing = new BMI();
$myBmiThing->height = $height;
$myBmiThing->weight = $weight;
$myBmiThing->bmi = $bmi;
$myBmiThing->date = date('r');

//Output JSON
echo json_encode($myBmiThing);