Need code explanation

Can someone please explain this code to me:

Why does the funtion call below take in two arguments:

type = Spry.Widget.Utils.firstValid(type, "none");

While it was defined without any argument:

Spry.Widget.Utils.firstValid = function() {
var ret = null;
for(var i=0; i<Spry.Widget.Utils.firstValid.arguments.length; i++) {
if (typeof(Spry.Widget.Utils.firstValid.arguments[i]) != 'undefined') {
ret = Spry.Widget.Utils.firstValid.arguments[i];
break;
}
}
return ret;
};

Any help and thought wellcomed.

Thanks.

Just part of how Javascript works; you're not required to specify all (or any) of a function's arguments. If you write a function that's expected to have a consistent number of arguments, then it's good practice to (and simpler to work with if you) specify them. But if your function may accept a variable number of arguments, then you might use something like what you've got there; all functions have an "arguments" object by which you can access the passed arguments by numeric index.

It's not an approach you should use without good reason though.

Thanks SambaNeko, u've just saved me 3 days of wondering. Thank you soo much.

It's not necessary to qualify arguments:

Code:

---

Spry.Widget.Utils.firstValid = function() {
        var ret = null;
        for(var i=0; i<arguments.length; i++) {
                if (typeof(arguments[i]) != 'undefined') {
                        ret = arguments[i];
                        break;
                }
        }
        return ret;
};

---

another improvement:

Code:

---

Spry.Widget.Utils.firstValid = function() {
        for (var i in arguments)
                if (typeof arguments[i] !== 'undefined')
                        return arguments[i];
};

---

Not really sure of the value of this function, to be frank.