Display a pop-up window containing an edit field. The button pressed to close the window is stored in an environment variable called EDITBOX and the characters entered in the edit field is stored in an environment variable called EDITBOXA.
EDITBOX "title" "prompt" ["default"]
title A string which specifies the window caption. prompt A string which is displayed above the edit field. default A string which specifies the default sequence of characters for the edit field.