How to tell if an object is $(document) inside a jQuery function?

Question

$.fn.foo = function() {
    console.log($(this));
};

$("#foo").foo();

$(document).foo();

How can I tell weather $(this) inside the function is $(document) or not?

In this question, people suggested

1. if (obj instanceof HTMLDocument)

2. if (Object.prototype.toString.call(obj) == "[object HTMLDocument]")

3. $obj.is('html')

but none of them works.

Yes, that is what I'm trying to prove, but the statement `$(this) == $(document)` returns `false`. — user1643156, Mar 22 '13 at 14:30
This won't work. Even `$(document) == $(document)` will result in false, as these are two different objects. — raina77ow, Mar 22 '13 at 14:30
No, this won't work either: `this` is a jQuery object, `document` is an Element one. — raina77ow, Mar 22 '13 at 14:34
@DavidFregoli read here - `this` is a jQuery object http://docs.jquery.com/Plugins/Authoring#Context — wirey00, Mar 22 '13 at 14:36
sorry didn't notice it's extending $. then just do this[0] == document — David Fregoli, Mar 22 '13 at 14:41

raina77ow · Accepted Answer · 2013-03-22T14:33:10.937

9

What about simple...

if (this[0] === document)

... as this inside jQuery function corresponds to jQuery object (not HTML one). Even if this object is empty, this[0] is still a valid expression - it's just undefined.

An alternative is to use jQuery is method:

if ($(this).is(document))

... as it accepts DOMElement as a param too.

edited Mar 22 '13 at 14:33

answered Mar 22 '13 at 14:27

raina77ow

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+1 saw you had the right answer so I waited.. but `this` doesn't need to be wrapped if it's inside the jQuery function – wirey00 Mar 22 '13 at 14:34

score 0 · Answer 2 · answered Mar 22 '13 at 14:41

0

$.fn.foo = function() {
    console.log(this[0] == document);
};

$("#foo").foo();

$(document).foo();

answered Mar 22 '13 at 14:41

waney

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maybe you should type faster next time. but thanks anyway. :) – user1643156 Mar 22 '13 at 14:44

How to tell if an object is $(document) inside a jQuery function?

2 Answers2