827585 - window.getSelection() returns null for hidden iframe

Status: REOPENED

(Core :: DOM: Selection, defect)

Description

[Tim Down]

Attachment: ffbug.zip

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/20100101 Firefox/17.0
Build ID: 20121128204232

Steps to reproduce:

Created an HTML document containing another HTML document in an iframe hidden via CSS display: none and examined the result of calling window.getSelection() in the iframe's document


Actual results:

null was returned


Expected results:

Per spec, since the iframe's document has a defaultView property, a Selection object should be returned. See 

http://dvcs.w3.org/hg/editing/raw-file/tip/editing.html#dom-window-getselection

Comment 1

[Loic]

Attachment: Reporter's testcase

Comment 3

[Boris Zbarsky [:bzbarsky]]

Actually, I guess we should just make the other depend on this one.

In any case, right now selection objects are tied to a presentation and there is no presentation in display:none iframes.  So fixing this bug requires revamping how selections work.  Well, or giving display:none stuff a presshell.

Comment 4

[Dennis Schubert [:denschub]]

P3 from a WebCompat perspective. We've only seen one live site breakage, and we could probably fix this via a site intervention.

Comment 5

[Richard Deeming]

I've just been bitten by this bug using a third-party script library on a page loaded into an iframe inside a Bootstrap modal dialog.

https://github.com/yairEO/tagify/issues/1338

The MDN documentation for getSelection makes no mention of the fact that the method could return null, which to me suggests this behaviour is not expected even if the page is in a hidden iframe.

Checking the document.visibilityState doesn't help, since that returns "visible". Similarly, document.hidden returns false.

Comment 6

[Randell Jesup [:jesup] (needinfo me)]

Given the recent webcompat breakage on EBay, this may need re-triage and effort assessment

Comment 7

[Andreas Farre [:farre]]

You know about selection, right? Do you have an idea of what's going on?

Comment 8

[Jan Jaeschke [:jjaschke]]

:sefeng and :denschub are already on it (in Bug 1967389).

Comment 9

[Sean Feng [:sefeng211]]

What Boris said in comment 3 is still valid.

Basically we don't have a presShell for display:none, so we don't get a selection.

According to the spec The method must return the selection associated with this if this has an associated browsing context, and it must return null otherwise, selection object should be associated with browsing context, so this is a bug in Firefox.

Looks like one fix we could fix this by moving the selection from presshell to browsing context, which doesn't look hard to do.