198534 - margin of child element is rendered outside border-less parent element

Status: RESOLVED INVALID

(Core :: Layout: Block and Inline, defect)

Description

[Andy Holmes]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.3) Gecko/20030312
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.3) Gecko/20030312

In the given example ( http://devel.rawendwebdesigns.com/margin_error.html ),
the margin of the h1 is rendered outside the containing div unless the div has a
border. Should be able to reproduce with any block element.

Reproducible: Always

Steps to Reproduce:
1. Put a block level element with margin inside one without.
2. Place another block level element so it renders above/below the above parent
element
3. Possibly colour both to better see the effect

Actual Results:  
The margin of the child-element is rendered outside the parent's box.

Expected Results:  
Rendered margin inside parent box.

Comment 1

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

This is how it's supposed to work.   See:
http://www.w3.org/TR/CSS21/box.html#collapsing-margins
http://www.w3.org/TR/CSS21/visudet.html#q19