Suppose we are editing a screen and playing with adding and removing columns and rows. The URLs to do these actions will be like these (note the last part):

http://localhost/zabbix/screenedit.php?config=1&screenid=16&add_col=0
http://localhost/zabbix/screenedit.php?config=1&screenid=16&rmv_col=0
http://localhost/zabbix/screenedit.php?config=1&screenid=16&add_row=3
http://localhost/zabbix/screenedit.php?screenid=16&rmv_row=3

These are GET requests, which means that pressing F5 or simply giving someone these links to go to will perform the corresponding action.