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Re: [cssom-view] Why is body's offsetParent null ?

From: Anne van Kesteren <annevk@opera.com>
Date: Wed, 23 Apr 2008 11:03:03 +0200
To: "Daniel Glazman" <daniel.glazman@disruptive-innovations.com>
Cc: "www-style@w3.org" <www-style@w3.org>
Message-ID: <op.t913fd2h64w2qv@annevk-t60.oslo.opera.com>

On Wed, 23 Apr 2008 10:52:54 +0200, Daniel Glazman  
<daniel.glazman@disruptive-innovations.com> wrote:
> Anne van Kesteren wrote:
>> document.body.getBoundingClientRect().top -  
>> document.documentElement.getBoundingClientRect().top
>>  or
>>  document.body.offsetTop - document.documentElement.offsetTop
> Excerpt from your own spec : "If A is the HTML body element or does not
> have an associated CSS layout box return zero and stop this algorithm".

I'm sorry. I'm still a bit sleepy I guess.

> So document.body.offsetTop is always zero and your last proposal above
> does not work.
> If only the first one is available, that means that for all elements
> but document.body, we use A.offsetTop and for document.body, we use
> A.getBoundingClientRect().top ??? That's really inconsistent and
> painful.

Actually, you would probably always use getBoundingClientRect() as that's  
far more consistent and reliable than any of the offset* attributes. They  
are mainly defined because lots of legacy scripts use them currently to  
calculate the position of an element using while loops (which the  
specification handles fine).

Anne van Kesteren
Received on Wednesday, 23 April 2008 09:03:24 UTC

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