Skip to content


Subversion checkout URL

You can clone with
Download ZIP


HTMLCollection issue #1530

w35l3y opened this Issue · 1 comment

2 participants

var _elements = document.forms[0].elements,
_collections = [HTMLCollection, unsafeWindow.HTMLCollection, window.HTMLCollection];
// returns true,true,false
// i suppose it should return true,true,true
alert( (v) {
    return !!v;

// returns false, true, "invalid 'instanceof' operand _i"
// i suppose it should return true, true, true
for each (var _i in _collections) {
    alert(_elements instanceof _i);

I am using Firefox 11.0 and Greasemonkey 0.9.18

(_elements instanceof HTMLCollection) was returning true before Firefox 11.0


I'm running: Mozilla/5.0 (X11; Linux i686 on x86_64; rv:10.0) Gecko/20100101 Firefox/10.0

My script says:

var e = document.links;
dump('e instanceof HTMLCollection: ' + (e instanceof HTMLCollection) + '\n');
dump('e instanceof unsafeWindow.HTMLCollection: ' + (e instanceof unsafeWindow.HTMLCollection) + '\n');
dump('e instanceof window.HTMLCollection: ' + (e instanceof window.HTMLCollection) + '\n');

I see in the console:

e instanceof HTMLCollection: false
e instanceof unsafeWindow.HTMLCollection: true

Then in the error console:

Mon Apr 23 2012 12:28:55
Error: invalid 'instanceof' operand window.HTMLCollection
Source file: file:///.../gm_scripts/elements_test/elements_test.user.js
Line: 11

This isn't new. And I don't think there's really anything we can do. I'd suggest you investigate

@arantius arantius closed this
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Something went wrong with that request. Please try again.