The guideline
Show suggestions after two or three typed characters, with no visible lag or flicker as the user keeps typing. Deduplicate and filter suggestions so nothing redundant or clearly irrelevant appears, and visually distinguish raw query completions from suggestions that point at a specific product, title or category. Tolerate near misspellings rather than returning an empty popup for a one-character typo. Implement the control as an accessible combobox, not a plain text input with a floating list glued on: arrow-key navigation highlights an option and can copy it into the field, Enter accepts the highlighted option, Escape closes the popup without altering typed text, and the relationship between the input and its suggestions is exposed with aria-autocomplete and aria-activedescendant (or equivalent) so screen reader users get the same capability sighted users do.
Common failures
- The site's search field does not display keyword query suggestions while the user types, forcing shoppers to formulate complete queries from memory and increasing the risk of zero-result or poorly framed searches.
Where it applies
Pages
Disciplines
Devices
Why it matters, how to fix it, and the research behind it
Rubric's full guide adds the reasoning, the fix and the sources for this check, and checks your client's pages against it and hundreds of others. Findings come back worst first.