Execution Context is one of the most fundamental yet most misunderstood concepts in JavaScript. It defines how JavaScript code is evaluated and executed, and it plays a central role in determining how variables, functions, and scope behave. Many core...

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Execution context is the fundamental mechanism that defines how JavaScript evaluates and executes code. The guide explains how the JavaScript engine works through JIT compilation, then breaks down the two types of execution contexts (global and function), their two phases (creation and execution), and how they form a call stack. Through detailed examples, it demonstrates how execution context explains hoisting (variables initialized as undefined during creation phase), scope (parent contexts accessible to children but not vice versa), and closures (inner functions preserving outer lexical environments). The guide also covers the temporal dead zone for let/const versus var behavior.

How Execution Context Works in JavaScript – A Handbook for Devs

Introduction to JavaScript Execution Context

Understanding Scope Through Execution Context

Understanding Closures Through Execution Context