You would need to identify the DOM object for the tab and build the HTML dynamically. Not sure how flexible this would be if you wanted to retrieve tabs dynamically (haven't seen an object for tabs before so don't know if it exists). Even if you were to do this, it would only work via custom visualforce pages. It would be pretty useless.
Not without Javascript.
How would you do it in javascript?
You would need to identify the DOM object for the tab and build the HTML dynamically. Not sure how flexible this would be if you wanted to retrieve tabs dynamically (haven't seen an object for tabs before so don't know if it exists). Even if you were to do this, it would only work via custom visualforce pages. It would be pretty useless.
Here is a simple but really good example of how to do it using jquery.
http://www.9lessons.info/2012/06/simple-drop-down-menu-with-jquery-and.html
Hope it helps to get you started!
Thanks Vishal, but the question is how to turn force.com tab into a drop-down menu. Any idea how I integrate your code into force.com?