Wolfram Language & System 11.0 (2016)|Legacy Documentation

This is documentation for an earlier version of the Wolfram Language.View current documentation (Version 11.2)


is an option for Dynamic, DynamicModule, Manipulate, and related constructs that specifies an expression to be evaluated when the construct is first displayed.


  • The typical usage is Initialization:>expr.
  • Initialization expressions defined in particular cells in a notebook are evaluated when those cells are first made visible, and not necessarily when the notebook is first opened.
  • Initialization expressions are guaranteed to be evaluated exactly once before the body of the main function is resolved.
Introduced in 2007