[whatwg] overflow of seamless iframes

Ian Hickson ian at hixie.ch
Thu Jul 31 14:11:08 PDT 2008

On Thu, 31 Jul 2008, L. David Baron wrote:
> http://www.whatwg.org/specs/web-apps/current-work/multipage/embedded0.html#seamless 
> doesn't seem to say what happens to overflowing content in seamless 
> iframes.
> Overflowing content seems likely to occur with the default values of 
> 'width' and 'height', in at least the case where content inside the 
> iframe that is wider than the iframe's containing block things like 
> floats inside the iframe
> I would suggest that the 'overflow' CSS property apply to the handling 
> of overflowing content inside seamless iframes.  This seems like it 
> would make them most like blocks.
> In any case, it seems like this ought to be defined (although if it were 
> defined by making a more general statement of equivalence that might be 
> good, since I suspect a bunch of other similar things are undefined as 
> well).

My original idea (apparently not well conveyed in the spec) is that it 
doesn't actually affect the rendering model at all -- it's still an 
<iframe>, it just doesn't have a border, and the CSS style sheets cascade 
into it and properties inherit into it. So the answer would be "do the 
same as with regular iframes", which I guess is to only support overflow: 
hidden and overflow: visible (and 'auto' mapping to one of those 
dynamically), as derived from the viewport as for any browser context.

Note that the default width and height are adjusted for seamless iframes 
to match the width that the element would have if it was a non-replaced 
block-level element with 'width: auto', and the height of the bounding box 
around the content rendered in the iframe at its current width, 

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

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