# Factorial Function Javascript

In this article, I would like to discuss how to create a factorial function in javascript. First, we understand how to find the factorial of a given number,

If I want to find the factorial of 5 then I will find “5x4x3x2x1”. So, let’s see how to find the factorial of 5 in a javascript program.

## Program

```
var num=5;
var fact=1;
for (var i = num; i >= 1; i--) {
fact=fact*i;
}
document.write(fact);
/*
output:
120
*/
```

Steps:

- In the above code, we created a variable “
**num**” and gave a value of 5. Because we are finding the factorial of 5, so we have given the value 5 for variable “num”.You must give the value of the number for which you want to find the factorial. - Then we have variable “
**fact**” and given the value 1. Because every factorial number ends in 1. - Then we created a “
**reverse for loop**” within that we assigned the variable “**fact=fact*i**“. - And print the variable fact. See the above output, the factorial number of 5 is displayed as 120 successfully.