StringLess
[b, a] → [stringLess(b, a)]

Adobe documentation

ActionStringLess

ActionStringAdd concatenates two strings.

FieldTypeComment
ActionStringLessACTIONRECORDHEADERActionCode = 0x29

ActionStringLess does the following:

  1. Pops value A off the stack.
  2. Pops value B off the stack.
  3. If B < A using a byte-by-byte comparison, true is pushed to the stack for SWF 5 and later (SWF 4 pushes 1); otherwise, false is pushed to the stack for SWF 5 and later (SWF 4 pushes 0).