Simple Array Question

[Falconix]

Is there a way to tell if a certian JS variable is an array or not? IE, some boolean function or method?

[jeffmott]

I believe the best you can tell is whether it is a number, string, object, or undefined. An array will show up as an object.var n = 16;
var s = "hello world";
var a = new Array(1, 2, 3);
alert(typeof n);
alert(typeof s);
alert(typeof a);

[Charles]

JavaScript does have a typeof operator (http://developer.netscape.com/docs/manuals/js/client/jsref/ops.htm#1042603) but Arrays in JavaScript are objects so it's not much help. But because Arrays are objects you have a couple of otions. You could give all Arrays a property called isArray and then test for it.

<script type="text/javascript">
<!--
Array.prototype.isArray = true;

giantSays = ['fee', 'fie', 'foe', 'fum'];
if (giantSays.isArray) {alert('I\'m an Array')}
// -->
</script>

Or you could overwrite Array.toString().

<script type="text/javascript">
<!--
Array.prototype.toString = function () {return 'Array'}

giantSays = ['fee', 'fie', 'foe', 'fum'];
if (giantSays == 'Array') {alert('I\'m an Array')}
// -->
</script>