How to check if an object is an instance of a NodeList in IE?

Question

Why is NodeList undefined in IE6/7?

Answer 1

"Duck Typing" should always work:

...

if (typeof el.length == 'number' 
    && typeof el.item == 'function'
    && typeof el.nextNode == 'function'
    && typeof el.reset == 'function')
{
    alert("I'm a NodeList");
}

Answer 2

I would just use something that always evaluates to a certain type. Then you just do a true/false type check to see if you got a valid object. In your case, I would get a reference to the select item like you are now, and then use its getOptions() method to get an HTMLCollection that represents the options. This object type is very similar to a NodeList, so you should have no problem working with it.

Answer 3

Adam Franco's answer almost works. Unfortunately, typeof el.item returns different things in different version of IE (7: string, 8: object, 9: function). So I am using his code, but I changed the line to typeof el.item !== "undefined" and changed == to === throughout.

if (typeof el.length === 'number' 
    && typeof el.item !== 'undefined'
    && typeof el.nextNode === 'function'
    && typeof el.reset === 'function')
{
    alert("I'm a NodeList");
}

Answer 4

With jQuery:

if (1 < $(el).length) {
    alert("I'm a NodeList");
}