A few years ago, I was stunned to find out that there were HTML elements that I wasn’t aware of that could impact how quickly a browser could render a page. I had been developing web pages for years and couldn’t believe there were tags I hadn’t encountered yet.
I then set out to learn every element by reading through the syntax guides and even reviewing the XHTML Transitional DTD. I learned about localization tags like <bdo> and rarely used tags like <dfn>. Any tag I didn’t recognize I read about.
Which is why I’m still reeling from the revelation that there is a scope attribute for <th> tags. According to Veerle and Roger Johansson, the scope attribute is important for accessibility. I didn’t think there were any HTML attributes I hadn’t encountered yet.
So while I glad to have learned a useful and important attribute for accessibility, I’m not looking forward to reviewing all of the attributes again to see if there is anything else I’ve missed. :-)