If you're looking to test your HTML knowledge (and who isn't?), take a trip to the justsayhi website. How many elements can you name in five minutes?
As an aside, the JavaScript built into the test is simple but perfect -- an idea carried out well.
As much as developers now loathe Flash, we're still playing a bit of catch up to natively duplicate the animation capabilities that Adobe's old technology provided us. Of course we have canvas, an awesome technology, one which I highlighted 9 mind-blowing demos. Another technology available...
For maximum performance, we all know we must put our assets on CDN (another domain). Along with those assets are custom web fonts. Unfortunately custom web fonts via CDN (or any cross-domain font request) don't work in Firefox or Internet Explorer (correctly so, by spec) though...
One of the little known JavaScript events is the image onError event. This event is triggered when an image 404's out because it doesn't exist. Broken images can make your website look unprofessional and it's important to fix broken images as soon as possible.
Working with textarea widths can be painful if you want the textarea to span 100% width. Why painful? Because if the textarea's containing element has padding, your "width:100%" textarea will likely stretch outside of the parent container -- a frustrating prospect to say the least. Luckily...
I make only 25 (the shame is over me :-D). I don’t know or remenber the existence of BDO, COLGROUP, ISINDEX, KBD, OPTGROUP, Q, SAMP, TT and VAR. The others i have a simple mind blank.