Re: [whatwg] behavior

Fri, 18 Sep 2009 07:21:48 -0700 

On Fri, 18 Sep 2009 08:18:04 -0400, Boris Zbarsky <[email protected]> wrote:


On 9/18/09 4:57 AM, Michael A. Puls II wrote:

We (Gecko) consider it a bug that a display:none <object> in a
document doesn't instantiate the plug-in.


BTW, what is the reason for considering it a bug?
Because the current behavior of having the plug-in instantiation handled by effectively the CSS box means that any time that box changes (e.g. when you switch from display:block to display:inline) the plug-in is reinstantiated. Worse yet, it can be reinstantiated due to other unrelated DOM mutations, depending on what effect they have on CSS boxes. That's pretty undesirable. 

O.K.


{
visibility: hidden;
width: 0;
height: 0;
padding: 0;
margin: 0;
line-height: 0;
font-size: 0
border: 0
}

is insufficient and or a pain when you want to load a plug-in but
completely hide it so it's as if it's not there layout-wise?
That CSS is a pain _and_ insufficient, depending on context. For example, consider the situation when the parent of that <object> is display:table-row. 

O.K.


Do you know of any sites that would work better if the bug was fixed?
Looking at https://bugzilla.mozilla.org/show_bug.cgi?id=90268 and its duplicates and depenencies, at least: 

http://reviewkaki.blogspot.com/
http://www.youtube.com/
Any site using Dojo 1.0.0 TabContainer with plug-ins in the tabs
and a number of cases where web site developers ended up having to work around this behavior or reported it without mentioning which site they were working on.
Funny enough, people want to be able to set paused Flash videos to display:none and back without losing their position in the video.... 

Thanks for this.


Know any sites that'd break or begin to unexpectedly load a bunch of
<object>'s that weren't meant to be loaded yet?
Not sure, but since as far as I now Opera and IE both keep the plug-in alive when the CSS box goes away, as far as I can tell, I'm rather hoping there won't be many. Not sure what webkit's behavior is here. Want to test? 

Attaching a test.

Results:
O.K., if the initial display state of the <object> is none, then Opera, Firefox, Safari and IE don't load the plug-in.
Then, once you set the display to inline, inline-block, block or table for example, the <object> will display and fire up the plugin. 

Then:

In Opera:
If you switch the display to none, it destroys the plug-in instance. Setting the display to something else again doesn't restore the previous plug-in instance. It creates a new one that starts playing from the beginning.
However, switching between inline, inline-block, block and table just changes the display and the plug-in keeps playing the file. 

In Safari:

Setting to a display of none destroys the plug-in instance like Opera.
However, switching between inline, inline-block, block and table destroys the current instance and creates a new one each time, which causes the plug-in to start playing from the beginning. 

In IE:
Once the <object> is shown for the first time, you can set its display to none, inline, inline-block, block and table and it will just change the display while letting the plug-in keep playing. This means that setting the display to none won't destroy the plug-in instance like it does in other browsers. 

In Firefox:

Same as Safari.
So, is it IE's behavior we want here, or Opera's? The difference being that display: none can kill an already-started plug-in in Opera (and other browsers right now), while in IE, I think you have to actually remove the <object> from the document to get rid of it, or perhaps change its @type/@classid etc.
Judging by the use-case you mentioned above, IE's exact behavior in these situations is what's desired?
Or, are you saying that the <object> should also load the plug-in even when its display is set to none by default?
Just want to make sure what's desired, if HTML5 matches it and what each browser has to change. 


If the change is trivial, maybe someone can throw up an experimental FF
or webkit binary with the fix.
If the change were trivial it would have been done back when the bug was filed, in 2001.
O.K. Thanks (thought maybe it was a political issue for why it wasn't fixed yet instead.) 

--
Michael
Title: <object> - plug-in loading & css

This document contains an <object> set to display: none by default. Use the dropdown below to change its display to various other values to see what happens in each browser each time you change the value.

none inline inline-block block table

Before_ You need flash! _After

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