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

1) When X=0 function should return 1; 2) Added return;

 function fact(num)
 {
    var x=parseInt(num);
    //alert(x+1);
    if(x>0)
        x=x* fact(x-1);
    else
        x=1;
    return x;
 }

usage