[css3-background] Background positioning area of root element when background-attachment is fixed from Daniel Tan on 2014-05-23 (www-style@w3.org from May 2014) (original) (raw)

On 5/23/2014 3:15 AM, Xianzhu Wang wrote:

Hi,

http://www.w3.org/TR/css3-background/#special-backgrounds says "the background positioning area is determined as for the root element". However I tested several browsers (Chrome, IE10, Firefox, Safari) and they all seem not to conform this.

Test case is like:

http://jsbin.com/pepufelo/1/ (gradient) and http://jsbin.com/pepufelo/2 (real image with background-size: 100% 100%) also allow you to toggle between 'fixed' and 'scroll' background-attachment by clicking on the page.

On my tested browsers, when background-attachment is fixed, the viewport (instead of the root element) is used as the background positioning area. I'm wondering if this behavior has been specified or is a known issue.

Thanks, Xianzhu

I believe this is specified under 'background-origin', which says:

If the �background-attachment� value for this image is �fixed�, then this property has no effect: in this case the background positioning area is the initial containing block [CSS21].

http://www.w3.org/TR/css3-background/#the-background-origin

-- Daniel Tan NOVALISTIC <http://NOVALISTIC.com>

Received on Friday, 23 May 2014 05:57:17 UTC