As promised in http://lists.w3.org/Archives/Public/public-webapps/2013AprJun/0685.html, I sketched out custom element declarative syntax using the "last completion value" idea:
https://dvcs.w3.org/hg/webcomponents/raw-file/tip/spec/custom/index.html#declaring-custom-elements Please look it over. I am sure there are bugs. Think of them as prizes for the first-graders' egg hunt. Of course, if you're a fourth-grader, you'll spot the eggs away. But you won't scream in delight. Because you're cool now. As I was writing this down, I ran into the following issues: https://www.w3.org/Bugs/Public/show_bug.cgi?id=22077: How to process "constructor name" of element declaration? https://www.w3.org/Bugs/Public/show_bug.cgi?id=22079: How to transfer callbacks when declarations are being processed by parser? https://www.w3.org/Bugs/Public/show_bug.cgi?id=22126: Should <element> support declaring SVG elements? Bugs 22077 and 22079 are rather disturbing to me. I would rather not introduce more places where parser runs script. :DG<
