Update factorial.js

Author: itsvinayak

maths/factorial.js

@@ -50,4 +50,4 @@ function calcFactorial (num) {
 // Run `factorial` Function to find average of a list of numbers.
 /* global alert, prompt */
 var num = prompt('Enter a number: ')
-alert(calcFactorial(num))
+console.log(calcFactorial(num))