Javascript, Fibonacci

function fibonacci(n)
{
if (n==0) return 0;
if (n==1) return 1;


var r1 = 0; //f0
var r2 = 1; //f1
var result = 0;

/* this work too
n = n-2
while ( n-- >= 0 )
{
result = r1 + r2;
r1 = r2;
r2 = result
}
*/

var i;
for ( i=2;i<=n;++i)
{
result = r1+r2;
r1=r2;
r2=result;
}
return result;
}

alert(fibonacci(10));