Custom attributes - Yea or nay?

Question

Recently I have been reading more and more about people using custom attributes in their HTML tags, mainly for the purpose of embedding some extra bits of data for use in ja

Answer 1

HTML 5 explicitly allows custom attributes that begin with data. So, for example,

Hello

is valid. Since it's officially supported by a standard, I think this is the best option for custom attributes. And it doesn't require you to overload other attributes with hacks, so your HTML can stay semantic.

Source: http://www.w3.org/TR/html5/dom.html#embedding-custom-non-visible-data-with-the-data-*-attributes