The global object in browsers

Ian Hickson ian at
Tue Feb 17 17:24:00 PST 2009

On Tue, 17 Feb 2009, Mark Miller wrote:
> On Tue, Feb 17, 2009 at 5:03 PM, Ian Hickson <ian at> wrote:
> >
> > Indeed, I noted this earlier. The behavior HTML5 codifies is the 
> > behavior that the majority of browser vendors have asked me to codify.
> Majority, huh? Which vendors? How does the behavior they ask for 
> correlate with what their browsers do?

Opera, Apple, and Mozilla. The HTML5 spec originally specced what IE does, 
namely throw an exception when running code whose global object doesn't 
match the current Window object, but Opera, Apple, and Mozilla rejected 
this on the grounds that it could not be implemented in a high-performance 
manner. They requested that the spec be changed to match what Mozilla and 
Safari do. What Opera does is known to be incompatible with deployed 
content (they expose Window objects that aren't === to each other).

The browsers all do slightly different things. The HTML5 spec right now is 
a mix of what Gecko and Webkit do.

Ian Hickson               U+1047E                )\._.,--....,'``.    fL       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'

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