New answers tagged html
not disagreeing with @jukka's opinion on using img / elements, but here's another version using input /s http://jsfiddle.net/leaverou/CGP87/light/
Dropdowns in html forms expand by default when they get focused and the down arrow key is pressed. So yes, I would recommend implementing this in your widget as many users certainly have taken this habit whereas only few of them might be comfortable with combined keys shortcuts like ALT+DownArrow.
Top 50 recent answers are included