fibonacci.php

var logger = console.log;//<?php function logger($msg) {echo "\n".$msg;};

function fibonacci($seq) {
    if ($seq < 2) {
        return $seq;
    } else {
        return fibonacci($seq - 1) + fibonacci($seq - 2);
    }
}

logger(fibonacci(10));

/**
 * The code above can be both compatible with JS and PHP.
 * I think I can write a program compatible both. 
 *
 * @gist https://gist.github.com/4043654
 */