penders - 10:31 pm on Jun 27, 2011 (gmt 0)
The part in the immediately preceding post-- allowing for the fact that the http part turned into a link, so my browser may have eaten the non-permitted parts of it.
Ah OK, but that part in @Kickedout's post was incomplete and did not 'look right'. I think the HTTP part turned into a link because double quotes were omitted around the URL (the system identifier) and the forum software (not the browser) automatically turned it into a link. It should be... "http://www.w3.org/TR/html4/loose.dtd" in double quotes.
As mentioned, the 2nd part of the DOCTYPE is the system identifier and is required in order to make it a full DOCTYPE. If you don't have a full DOCTYPE you might trigger quirks mode (ie. non-standards mode) in certain browsers, notably IE.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
Yep, used on this very site! Unfortunately WebmasterWorld.com is not leading by example here - this DOCTYPE should not be used on your nice new website. Legacy sites only. This part DOCTYPE specifically triggers quirks mode in all browsers! Which means you are unlikely to get any two browsers looking the same (8 pixels here, 8 pixels there, etc.) This site for instance has different padding/margins/positioning in IE than Chrome (this doesn't really matter in this case since functionality out ways design - it "works").
With the "..." missing in Kickedout's DOCTYPE this is probably resulting in a part DOCTYPE and triggering quirks mode in the browser.