ℹ️Teaching model: traces supported declarations, function calls, scope resolution, hoisting, this, and closures. It does not execute arbitrary JavaScript or expose a browser engine's real memory.
JavaScript Code EditorDirectly edit or paste custom code
Step 0 of 0
←→StepSpaceRun
Press → (Step) or Space (Run)
Phase 1: Compilation(Hoisting & Memory Setup)
➔
Phase 2: Execution(Line-by-line Evaluation)
Execution Step Breakdown

Press "→" / click "▶" to step line-by-line, or press "Space" / click "▶ Run" for auto-play.

Written guidesHow JavaScript Executes Code: From Global Code to Function ReturnJavaScript Hoisting: Declarations, Initialization, and the Temporal Dead Zone