Is there a succinct explanation of why the is= syntax is disliked? The info on the WHATWG wiki explains where is= breaks, but doesn’t offer much on the syntax issue [1].
Léonie. [1] https://wiki.whatwg.org/wiki/Custom_Elements#Subclassing_existing_elements -- Léonie Watson - Senior accessibility engineer @LeonieWatson @PacielloGroup PacielloGroup.com