Hello,
Re: Button in Web UI alike the more button
Check the above thread
There is a test UIU component where you can find different usages of Tag libraries.
For buttons,
Go to component workbench
Execute component "CRM_THTMLB_COMP" navigate to "button" pages. Here you can see many of the variations of Buttons tag.
Implement the one which is suitable for you.
Hope it helps,
Regards,
Ashik