When you don't have need of an alt attribute, add one but keep it empty. In the absence of an alt attribute some screen readers will read out the path of the image instead. Setting it to empty allows you to remove this, almost always, unnecessary noise.
The mention of Fangs alone made this article valuable to me. Accessibility has had lots of lip service for years but it is essentially impossible to do any legitimate work optimizing for screen readers if you don't have access to them (being prohibitively expensive.) It's like writing for a browser you never get to test in. If anyone was serious about accessibility they should get simply get screen readers in the hands of the people building web sites.
It's completely legitimate to have an input tag outside of a label. Even the link you provided states:
The HTML <label> Element represents a caption for an item in a user interface. It can be associated with a control either by using the for attribute, or by placing the control element inside the label element.
Number 2 is simply misleading. It doesn't take in consideration HTML 5 Document Outline speification. It's not enough anymore to simply use h1-6 accordingly. You must take the whole document landing marks sructure in account (`article`, `section` etcetera.)
Number 8 is not completely correct anymore. Javascript was recently included in the accessible tecnologies. Screen readers nowadays do own a DOM and a full rendering stack. ARIA, in fact, dictates a lot of interesting accessibility states and tools. That said, I do not push forward the use of javascript for structural functionalities, the rule that states that "Javascript is an enhancement" still works and will always work, but excluding enhancements for accessibility is naïve as far as the naïvete of the implementation.
Not really misleading: most screen readers aren't yet using the HTML5 Document Outline algorithm, so for accessibility you still have to rely on proper h1-6.
Ideally, you'd use them in combination for future proofing. It takes a little work, but you can arrive at the same general outline from both algorithms, since the new one ignores the ordinality of the h tag.
In my experience many screen reader users aren't on the latest version of their accessibility software (cost and effort are among the reasons). So it's not uncommon for users to be using screen reader software that doesn't account for HTML5 elements.
please. build for people, not validators. it's good to check for mistakes, but validators are far from a stamp of approval for anything. know what you're doing instead of seeking 'validated' crap.
People generally don't read HTML... machines do; the further levels of validation you can obtain (and certainly to the extent to which the code is somewhat valid at all, such as making certain to have tags that aren't misusing quotation marks or brackets or entities), the more likely your code is to be understood in the same way by random implementations of HTML parsing that may be used in the field.
yeah, I remember injecting flash objects with javascript wrapped in cdata, so the w3c validator confirms my awesome coding skills in green, good times. now I treat validators as useful tools for double-checking syntax, and nothing else. it validates more often than not anyway, but it's not that I care.
invalid code doesn't mean shitty code, and the other way around - being valid doesn't say anything about the practical quality of code. know your craft = know the rules + know when you can break them.
Here's the thing: It's not uncommon to come across weird bugs/rendering errors on web pages that were caused by incorrect HTML (where the developer writes </a> where he should have written </p> and similar issues). Pages with those kind of errors might render fine in Browser X and yet have render errors in Browser Y. That's why you validate - to find those kind of bugs.
Unfortunately on the topic of accessibility you're likely going to need to design for people, but build your site to validate. I don't have much experience using screen readers, but from what I can tell they're going to need at minimum well build HTML.
Well, yes (build for people) and no (stuff should be technically correct, as well).
For instance, the WGAC 2.0 guidelines require that HTML be valid, and if a client wants WGAC 2.0 compliance (even A level, not AA), the site's gotta validate [1].
unless you are doing it for bureaucracy's sake (public sector, etc.), do what works, not what some ink on paper from half a decade ago says, otherwise it's CYAE[1].
Regarding JavaScript: some JS-heavy apps can be made accessible easier than it looks at the first sight. One just needs to use <input> and <button> or <a> for binding 'onclick' events, instead of <div>s, <span>s etc. [1] and perhaps add some additional code to handle quirks in some browsers.
When you don't have need of an alt attribute, add one but keep it empty. In the absence of an alt attribute some screen readers will read out the path of the image instead. Setting it to empty allows you to remove this, almost always, unnecessary noise.