Table with embedded button to show more rows

This is a prototype of a table that allows the user to add more rows by activating a button. When the button is activated, more rows are shown and focus moves to the first of the new rows. aria-expanded is then set to true on the button itself.

col1 col2 col3
foo1 foo2 foo3
foo4 foo5 foo6
foo7 foo8 foo9
first of new rows bar1 bar2
bar3 bar4 bar5
bar6 bar7 bar8