Factorial Programming

Ahh, man, anyone here can show me how to perform factorials in JavaScript? I tried a long long time, still failed.

Code:

---

function FACTORIAL(n){
var i,e,f;
for(i=1;i<=n;i++){
e=i;
f=i;
e=e*f;
document.write(e + ", ");
}

---

unfortunately, this would work perfectly if it was getting squares for n, but please help me.

function FACTORIAL(n){
var i,e,f;
e=1;
for(i=2;i<=n;i++)e*=i;
document.write(e + ", ");
}

Thank you, wit.