how to active text field ?

Hello

following script is an example script in macroscript help...
could somebody tell me how to make text field to be active : no need to mouse clic in ????

macroScript RenameThem category:"HowTo"
(
rollout rename_rollout "Enter New Base Name"
(
edittext base_name ""
button rename_them "RENAME SELECTED OBJECTS..."
on rename_them pressed do
(
if base_name.text != "" do
for i in selection do i.name = uniquename base_name.text
)--end on
)--end rollout
createDialog rename_rollout 250 50
)