Determine if the combined HTML field will expand or collapse

Question

I need to determine through Javascript if the dropdown is expanding or dropping.

When the user clicks on the drop-down list, he gets focus and expands, and after choosing an option, he focuses, but looks minimized. I don't care about the trick, I need to test the crumbling.

How can i do this?

thanks

[Edit] I am using the plain old <select>

Answer 1

How about checking the visible children of a dropbox div?

Answer 2

In Firefox (with the Firebug extension installed), see which CSS classes apply to drop-down lists when expanding and dropping it. If there is a class unique to when the field is in a collapsible state, you can use Javascript to check if the class with the list has this class.

Or, if you control the combobox yourself, you can add or remove a CSS class so that you know what is from this state.