factorial of a number

Question

I have the following code but it is not giving perfect result for factorial can u find it out plz

Answer 1

var factorialNumber , factorial=1;
factorialNumber=prompt("Factorial Number" , "write Factorial Number");
for(var i = 1; i<= factorialNumber;i++){
    factorial *= i;
}
alert(factorial);

The code above first defines two variables, factorialNumber and factorial. factorial is initialized with 1. factorialNumber will get the result of the prompt (a number is expected) and then, using a cycle, in each step, factorial is multiplied with the index of the step, which is represented by i. When successfully calculated, we show the result using alert.