I am wondering why doesn't phpmyadmin have a confirmation on close of tab or browser while the user in inserting/editing a column.

It can be easily done by adding a piece of javascript code as in this fiddle http://jsfiddle.net/gopi1410/yWs7P/4/

  http://stackoverflow.com/users/1135703/gopi1410

  http://careers.stackoverflow.com/gopi1410