http://xfx.net/utilities/dmbuilderde/help/Samples/combobox/

Here's how this project works:

• The .dmb project is very simple: it only contains a toolbar, a toolbar item and the DynAPI template.
• The colors have been adjusted so the menu items resemble the standard Windows 3.1/Windows 95 comboboxes: white, black and blue.
• The rest is all DynAPI and a simple function to change the selection. Here's the source code:

http://www.marghoobsuleman.com/jquery-image-dropdown

http://www.baytree-cs.com/combo-select-box.html

DHTML Combobox

Currently HTML forms are missing a “combobox”. This control, familiar to traditional GUI programmers, combines the “text box” and “drop down select list”. Users can either select a value from the list, or type in their own value. I spent a lot of time looking around the internet for a “combobox” that would do what I wanted it to do but could only find partial answers, eg. they would work great in IE but not in Mozilla browsers or the definition of a “combobox” wasn't quite the same as mine.