Question

Here is the script, I don’t understand why it doesn’t work…

function FirstFactorial(num) {

var lower = num - 1;
var qq = 0;

while (num > 0) {
var qq === num * lower;
num--;
lower--;
}
num === qq;
return num;
}
FirstFactorial(num);

Answer 1

You have quite a few issues with this function, see the comments.

function FirstFactorial(num) {
    var lower = num - 1;
    var qq = 0;

    while (num > 0) {
        // here you are shadowing the "qq" variable in the outer scope
        // delete the "var" keyword to fix this
        // also === is an identity operator, i think you wanted assignment (=)
        // so this line becomes: qq = num * lower;
        var qq === num * lower;
        num--;
        lower--;
    }

    // assuming that === was supposed to be = again
    // you can rewrite this as just: return qq;
    num === qq;
    return num;
}

FirstFactorial(num);

Even with these syntactical fixes, your logic for calculating factorial is not correct.

Edit: working examples (because I was bored) http://jsfiddle.net/gU2cz/