nce of Form Abstraction Ezra Cooper, Sam Lindley, Philip Wadler, and Jeremy Yallop School of Informatics, University of Edinburgh Abstraction is the cornerstone of high-level programming; HTML forms are the principal medium of web interaction. However, most web programming environments do not support abstraction of form components, leading to a lack of compositionality. Using a semantics based on idioms, we show how to support compositional form construction and give a convenient syntax.