According to the principle of least astonishment, things should operate in a way that’s predictable. The collaborative nature between designer and developer is necessary for a universally usable system. The designer creates something that is visually predictable while the developer creates something programatically predictable.
As web developers we like to think that our hard work creating HTML, CSS, and JavaScript is what makes our sites so great. Then we realize the reality: all our hard work is really just a request saying, “Please, Mr. Browser, can you make this website do all the cool stuff I’ve designed here?” When the user’s browser receives your web page and all of its assets, your control of the situation entirely ceases. How your site really looks and operates is entirely in the hands of the browser.
In this talk, Karl provides important technical insight into accessibility by describing the interactions between HTML/ CSS/ JavaScript, the DOM, the BOM, Accessibility APIs and Assistive Technologies.