User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.5) Gecko/20031007 Firebird/0.7 Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.5) Gecko/20031007 Firebird/0.7 The example URL contains several floated images in an attempt to make an image gallery. There is a large DIV around all the images that does not contain the floated images. Hence the box only shows surrounding the text at the top of the box. This behavior is apparent in Mozilla 1.5 and Firebird 0.7. Opera and IE 6.0 display the surrounding div as containing the floated images. As far as I can tell this is valid HTML (according to the RFC). Reproducible: Always Steps to Reproduce: 1. Open Test Case Actual Results: The surrounding does not enclose the floated images, only the test text. Expected Results: The surrounding div should inlcude the text as well as all the thumbnails.
This is correct as far as I know. Floats are "removed" from the flow, see: http://www.w3.org/TR/REC-CSS1#floating-elements You have to add <div style="clear:both;"></div> to the end of the body_frame div to achive what you want.
Marking INVALID per comment 1, besides, you should read the CSS and HTML specification more carefully, since your complete document is relying on Mozilla's quirk rendering mode.