This page puts IE in quirks mode. Here a width includes padding and border (border-box width). But a percentage width on a child does not use as reference the border-box of the parent.
Similar cases as above, but with some margins on the child boxes. These show that a percentage width is not even computed on the basis of the content-box of the parent, but on the available width, i.e. the content box of the parent minus the child horizontal margins. So width:100% is the same as with:auto for a normal box (except that 100% adds hasLayout).
This page in standard mode: IE, percentage width and box model - standards. A similar page testing height instead of width IE/Quirks, percentage height and box model: the behavior is slightly different since the percentage is computed on the basis of the content-box of the parent.
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