In plain English
Picking an option or typing in a field should not, by itself, fire off a page change. Imagine choosing your country from a dropdown and the page instantly reloads before you have finished, or ticking a box and being whisked to a new screen. That is unpredictable, and for keyboard and screen-reader users it can be impossible to recover from.
The fix is simple: let people make their choices, then act on a real button.
Who this is for
- Keyboard users, who move through options and cannot predict auto-actions.
- Screen-reader users, who lose their place when the page changes silently.
- Anyone, who finds “it did something before I was ready” frustrating.
What “good” looks like
Collect input, then change things on an explicit action.
<!-- Good: nothing happens until "Apply" -->
<select name="country">…</select>
<button type="submit">Apply</button>
<!-- Acceptable: only if clearly announced beforehand -->
<label>Country (prices update automatically when changed)</label>
<select name="country" onchange="update()">…</select>Where stores get it wrong
Country, currency, or sort dropdowns that reload the page on change with no warning, and filters that navigate the moment a box is ticked. Catch these in a self-check; they sit alongside other predictability issues on the common failures list.