Wed 20 Jun 2018 11:00 - 11:25 at Grand Ballroom AB - Web Pages Chair(s): Tobias Wrigstad

Usability and accessibility guidelines aim to make graphical user interfaces accessible to all users, by, say, requiring that text is sufficiently large, interactive controls are visible, and heading size corresponds to importance. These guidelines must hold on the infinitely many possible renderings of a web page generated by differing screen sizes, fonts, and other user preferences. Today, these guidelines are tested by manual inspection of a few renderings, because 1) the guidelines are not expressed in a formal language, 2) the semantics of browser rendering are not well understood, and 3) no tools exist to check all possible renderings of a web page. VizAssert solves these problems. First, it introduces visual logic to precisely specify accessibility properties. Second, it formalizes a large fragment of the browser rendering algorithm using novel finitization reductions. Third, it provides a sound, automated tool for verifying assertions in visual logic.

We encoded 14 assertions drawn from best-practice accessibility and mobile-usability guidelines in visual logic. VizAssert checked them on on 62 professionally designed web pages. It found 64 distinct errors in the web pages, while reporting only 13 false positive warnings.

Wed 20 Jun
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11:00 - 12:15: PLDI Research Papers - Web Pages at Grand Ballroom AB
Chair(s): Tobias WrigstadUppsala University
pldi-2018-papers11:00 - 11:25
Pavel PanchekhaUniversity of Washington, Adam T. GellerUniversity of Washington, USA, Michael D. ErnstUniversity of Washington, USA, Zachary TatlockUniversity of Washington, Shoaib KamilAdobe
Media Attached
pldi-2018-papers11:25 - 11:50
John VilkUniversity of Massachusetts, Amherst, Emery BergerUniversity of Massachusetts, Amherst
Media Attached
pldi-2018-papers11:50 - 12:15
Samuel BaxterUniversity of Massachusetts at Amherst, USA, Rachit Nigam, Joe Gibbs PolitzUniversity of California, San Diego, Shriram KrishnamurthiBrown University, USA, Arjun GuhaUniversity of Massachusetts, Amherst
Media Attached