Detecting javascript array type

DebbieLeigh · Apr 24, 2004

Hi,

Can anyone tell me how I can detect whether a variable is an array in javascript. I've found that typeof returns 'object' for an array, but doesn't go any farther than that.

So, does anyone know of a way to go beyond this and distinguish between arrays and other types of objects?

Debbie-Leigh

vongrunt · Apr 24, 2004

Code:

if (blah [b]instanceof[/b] Array) alert("Yep, array");

BillyRayPreachersSon · Apr 25, 2004

You can also compare the "constructor" property:

Code:

<html>
<head>
<script type="text/javascript">
<!--
	var myArrayConstructor = new Array().constructor;
	var myCollectionConstructor = document.getElementsByTagName('body').constructor;

	var myArray = new Array();
	var myCollection = document.getElementsByTagName('body');

	alert(myArray.constructor == myArrayConstructor);
	alert(myCollection.constructor == myCollectionConstructor);
//-->
</script>
</head>
<body>
</body>
</html>

Hope this helps,
Dan

BillyRayPreachersSon · Apr 25, 2004

Incidentally, I couldn't work out any way to create a new collection without calling a method (such as getElementsByTagName) that returns one.

Does anyone know of a way? I'd be interested to find out. That way, the instanceof could also be used with collections.

Dan

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Detecting javascript array type

DebbieLeigh

Programmer

vongrunt

Programmer

BillyRayPreachersSon

Programmer

BillyRayPreachersSon

Programmer

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