Need code explanation

[Apparrel]

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.

[SambaNeko]

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.

[Apparrel]

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

[penagate]

It's not necessary to qualify arguments:

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;
};

[penagate]

another improvement:

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.