I have a friend that likes to use on all his browsers & computers a custom HTML page as the Home page. The page is pretty basic: a table with a number of links and a few images from webcams overlooking parts of the Panama Canal. The page gets refreshed periodically using the "classic" Meta refresh method:
<meta http-equiv="refresh" content="20;">
All simple & sweet except that in IE9 none of the images got refreshed (most have time stamps so it was easy to see) although the page itself got refreshed. In Chrome everything got refreshed without problems.
Opening IE9's Developer Tools I've noticed that the Document Mode was set to quirks and on refresh in the Network tab for all images it listed aborted in the Result column instead of a numeric HTTP result code.
After forcing the Document Mode to IE9 the images began refreshing. So the next step was finding out how IE9 sets the Document Mode. Fortunately the documentation was pretty easy to find (i.e. here) & the fix was adding a <!DOCTYPE> directive.
What I couldn't find was why the strange behavior of not (re)loading external resources on refresh. Quirks mode indeed...