The best replacement for script is screenplay.

The best alternatives to script are rated as following:
★★★★★  screenplay
★★★  program
★★★  cursive
★  code
★  print
★  novel
★  transcript
★  batch programming
★  schema
★  scrip
★  storyboard first
★  storyboard
★  macro
★  block lettering
★  batch
★  test case
  prescription
  query
  script
  batch file
  block phase 90
  shooting script
  java script
  function matlab
  server side script
  noscript
  vb script
  cursive writing
  scribe
  language
  story
  vbscript
  manuscript
  spec script
  java applet

Your alternative for script is not listed? Suggest!
Speaking about script, one probably shouldn't forget about expect.

Other search terms related to script and their ratings are:
★★★★★ expect
★★★★ stage directions
★★ 5 characters
★★ ssh
You have in mind a companion for script and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of script in all years. Click on graph for more.
script
screenplay
program