Reason for difference in behaviour of autcomplete interactions in input fields

Question

There seems to be two different schools of thought when it comes to the autocompletion of input fields and I am wondering if there is a particular reason or rationale for each.

Basically, when the user is completing an input field (usually text based) it is typical for autocomplete functionalities to be implemented when there has been previous inputs provided. The user can then choose to continue completing the input or to use the autocomplete feature by:

• Pressing the ENTER key
• Pressing the TAB key

Alternatively they can use the mouse and click on the autocomplete suggestion but it breaks the flow of typing from the keyboard.

Is there any particular reason (both from a technical AND user perspective) why some sites use the ENTER key while others use the TAB key for this? I think it creates a confusion because it is likely for a user to go to websites that implement this feature both ways.

Answer 1

One more scenario is gmail autocomplete, which uses the forward arrow key to accept the suggestion.

It’s also a case where TAB and ENTER are reserved for email composition purposes.

Maybe the trigger changes based on what’s available depending on the ui context. And based on the user’s familiarity or best guess with that ui.

For example, ENTER in search bar often mean running the query. Selecting a suggestion on a suggestive dropdown can be done with mouse+click, arrow down or tab+ENTER, etc since all of those are free to use in that context (with click and ENTER doubling as selection and running the query).

If the context is changed to that of sharing a doc, that click or ENTER changes to selection only, since in that context users are likely to to add more people to the sharing list. The cost of assuming the click or ENTER also mean “share” is too high.

In summary, maybe there is no standard because there are too many contexts. Standards probably exist per use-case (text editor vs search bar vs sharing), and is based on user familiarity and expectations.