The Missing Mechanic: Behavioral Affordances as the Limiting Factor in Generalizing HTML Controls

Abstract

In this paper, we analyze a set of three proposals—titled Triptych—which carefully extend HTML to support more generalized hypermedia controls. We evaluate the expressive power of these proposals by demonstrating which user experience patterns they make possible to describe in HTML, and which patterns remain unsupported. We also introduce the concept of behavorial affordances which characterize common UX patterns in web applications. Through this analysis of UX patterns, we show that HTML currently lacks a native mechanism for expressing behavioral affordances. Finally, we theorize a mechanism for defining arbitrary behavioral affordances that could fill this expressive gap.