HTML step attribute

[michael-n-cooper]

Need feature for step attribute. https://www.w3.org/TR/html51/sec-forms.html#the-step-attribute

Tracker issue: https://www.w3.org/WAI/ARIA/track/issues/539

[cookiecrook]

From original tracker issue: "Add aria-valuestep for feature parity with step attr on HTML 5 range input (slider). There is currently no way to programmatically determine an acceptable value within a range, so otherwise sliders implementing valueChangeRequest would need to accept any floating point value between min and max."

[cookiecrook]

If ARIA 1.2 is still limited to HTML Role Parity, this issue is not in scope.

[jnurthen]

also https://www.w3.org/Bugs/Public/show_bug.cgi?id=27870

[jnurthen]

So it seems that UIA and ATK map this -

UIA | If the input is in the Range state, set both RangeValue.SmallChange and RangeValue.LargeChange to the value of step.
Exposed as atk_value_get_minimum_increment if the element implements the AtkValue interface.

so for completeness we should probably do this.

Anyone want to do this in 1.3? If so please assign yourself.

[scottaohara]

Will throw my hat in for a try at this.

[joanmarie]

While ATK has this, Orca doesn't use it. What is the use case of step and who would consume it?

[joanmarie]

i.e. Does nsAccessibility support this and VoiceOver need it?

[jnurthen]

@cookiecrook should we close?

[cookiecrook]

Yes, but for posterity, here's a somewhat-related scenario.

• Some site (don't recall which) used a native slider with 3–4 values, and used JavaScript to enforce the slider thumb would land on the closest "step", but they didn't use the native step attr. Yes, I agree "Don't Do That™", but here's the scenario.
• Let's call it 4 total steps for illustration. Each value change equals 25%.
• VoiceOver-triggered steps default to about 10%, which is less than half of the 25% custom "step" delta.
• The Slider started at 0%, next closest "step" at 25%.
• VoiceOver user-triggered increment sets the slider value to 10%.
• The web app detects the value change, then uses JavaScript to enforce locking it to the nearest value, 0% (not the 25% user intention).
• To the user, it seems like the slider is broken. "I've incremented from 0, but it's still set to 0, or gets reset to 0."

So if custom ARIA sliders are ever able to allow more granular control (setValue or similar), the aria-valuestep attribute proposal may be worth revisiting. Currently it does not seem like that will happen anytime soon (maybe never), since we can get by with simulated keypresses (arrows, pageup, etc.)

TLDR: I am okay closing this issue, with the understanding that it might be necessary later if something like a setValue API is implemented.