使用JS的阶乘函数

Question

I wrote a code that accepts numbers and prints their factorial to the console.

This time, I wanna make it PROMPT a user for the number and then ALERT the factorial.

 var x = prompt("Input the number" ); var y=1; function factorial(x) { for(i=2; i<=x; i++) { y *= i; } console.log(y); } alert(factorial(x)); 

Answer 1

Your code is almost correct, you only forgot to actually return the value of y as the result of your function.

 var x = prompt("Input the number" ); var y=1; function factorial(x) { for(i=2; i<=x; i++) { y *= i; } console.log(y); return y; } alert(factorial(x)); 

Note the return y statement I have added.