<script type="text/javascript">
	function fibonacci(x)
	{
		if (!isNaN(x))
		{
			var output = document.getElementById('output');
			
			var a,b,c;
			
			a = 1;
			b = 1;			
			
			switch (parseInt(x))
			{
				case 1:
					output.innerHTML = '0';
				break;				
				case 2:
					output.innerHTML = '0 1';
				break;
				case 3:
					output.innerHTML = '0 1 1';
				break;
				case 4:
					output.innerHTML = '0 1 1 2';
				break;
				default:
					output.innerHTML = '0 1 1 2 ';
					c = a + b;
					for(var i = 4; i <= x-1; i++)
					{
						a = b;
						b = c;
						c = b + a;
						output.innerHTML += c + ' '; 
					}
				break;				
			}
		}
		else
		{
			alert('Það má bara slá inn tölur!');
		}
	}
	
</script>
<input type="button" value="Fibonacci" onclick="fibonacci(prompt('Hvað viltu margar tölur? Sláðu inn tölu á bilinu 4+'));" />
<div id="output"></div>

<?php
$aReturn = fibo(500);
echo "<pre>";
print_r($aReturn);
echo "</pre>";
function fibo($x='5')
{
        $aFib = array(
                '0' => '0',
                '1' => '1',
                '2' => '1',
                '3' => '2',
                '4' => '3'
        );
        for( $i = 5; $i <= $x; $i++ )
        {
                if( !isset( $a1 ) )
                {
                        $a  = array_values( $aFib );
                        $a1 = (int)array_pop( $a );
                        $a2 = (int)array_pop( $a );
                }
                $t = $a1 + $a2;
                $r = array( $i => $t );
                $aFib = array_merge($aFib, $r);
                $a2 = $a1;
                $a1 = $t;
        }
        return $aFib;
}
?>