Question regarding calculator :

Question

Finally I made a calculator , but I struck at a point ,
I defined a function to for finding the factorial of any number , first I added the symbol like this .
function f(val) {
document.getElementById('d').value+=val;
}
I don't know now how will I give the factorial as output on the screen of my calculator , Plz help .
Note : Plz don't write down the portion to find the factorial , I already know it , just tell how can I display it .
Thanks in Advance .

Answer 1

I don't know javascript much but this may work
suppose you have stored the factorial in variable "x"
then
var y = document.getElementById('d');
y.innerHTML = x;

Answer 2

That's not possible it becomes an error . Is there any other way.
I tried to store the factorial as an exception and then define it in the last , but then the value of "value" and "val" came out of function . And then its again an error .