I was wondering if the use of sliders would make it harder for people with disabilities to select values. How hard is it to drag and drop for them? How easy is it for them to see values changing while moving a different element, or to select a specific value?
Sliders are an enhancement--not a replacement for data entry. Anyone with motor skill difficulties may have trouble with sliders, so you want to ensure that the input values can also be manually entered via the keyboard. This requires that you make the value field visible and focus-able.
The markup should produce an input field by default:
Then via JS you'd 'enhance' this by adding the slider, which, in turn, would update the text field (and conversely, if you manually update the text field, it should update the slider).
Note that HTML5 now includes the
There's no bad or good components, it depends on implementation. In general slider isn't very accessible UI component, but you could make it better.
So, my recommendation - if you think, that you need slider, use it, but make it accessible. And, of course, test test test.