I am trying to find the most usable/accessible way to implement a simple form dropdown list which will sort a list of products by pice and alphabetical order.
In your opinion is the dropdown more usable when there is a button that governs its submission or when it automatically submits onchange of the dropdown?
The research I have read is both for and against such methods and there is a variery of implementations on the web so interest to hear the thoughts of the community.
Thanks in advance
So long as you do not change focus or navigate to another page when the selection changes, either approach should work. The classic example of a problem dropdown is where it contains a list of other pages on the site, and navigates as soon as the selection changes. This prevents a keyboard user from using the list; they can't browse it, and can't navigate to any pages beyond the first selection, since it's impossible to navigate past those. So in cases where focus changes or the page navigates as a consequence, having a separate action (eg. Go button, or handling enter) to cause the navigation to take place is essential. This is likely where the advice you've read is coming from.
In this case, however, it sounds as though you are just updating content elsewhere on the page, and not changing focus or doing navigation. Simply resorting existing content should be fine.