What execution context is in Javascript - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an execution context in JavaScript?

An execution context is the environment where JavaScript code runs. It holds information like variables, functions, and the value of 'this'.

beginner

Name the three main types of execution contexts in JavaScript.

Global execution context, Function execution context, and Eval execution context.

intermediate

What does the 'this' keyword represent inside an execution context?

'this' refers to the object that is currently executing the code in that context.

intermediate

What happens when a function is called in terms of execution context?

A new function execution context is created and pushed onto the call stack to run the function's code.

intermediate

How does the JavaScript engine manage multiple execution contexts?

It uses a call stack to keep track of execution contexts, running the top one and removing it when done.

What is the first execution context created when JavaScript code runs?

A Eval execution context

B Function execution context

C Block execution context

D Global execution context

The global execution context is created first and represents the outermost environment.

When a function is called, what happens to the execution context?

A The global context is replaced

B The function runs without any execution context

C A new execution context is created and added to the call stack

D The previous context is deleted

Each function call creates a new execution context pushed onto the call stack.

Which of these is NOT part of an execution context?

A Call stack

B Lexical environment

C 'this' binding

D Variable environment

The call stack manages execution contexts but is not part of a single execution context.

What does the 'this' keyword refer to inside a function execution context?

A The object that called the function

B The global object always

C The function itself

D Undefined

'this' refers to the object that called the function, depending on how the function is called.

What is the role of the call stack in execution contexts?

A To store variables

B To keep track of execution contexts in order

C To execute code asynchronously

D To manage memory allocation

The call stack tracks which execution context is currently running and manages their order.

Explain what an execution context is and why it is important in JavaScript.

Think about the environment where your code runs.

Describe how the call stack and execution contexts work together when functions are called.

Imagine stacking plates when you call functions.