Global scope in Javascript - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is global scope in JavaScript?

Global scope means a variable or function is accessible from anywhere in the code, no matter where it is used.

beginner

Where are variables declared outside any function or block stored?

They are stored in the global scope and can be accessed anywhere in the program.

intermediate

What happens if you declare a variable without let, const, or var inside a function?

It becomes a global variable, which can cause bugs because it is accessible everywhere.

beginner

How can you avoid polluting the global scope?

Use let, const, or var inside functions or blocks to keep variables local.

intermediate

What is the global object in browsers and how is it related to global scope?

In browsers, the global object is window. Variables in global scope become properties of window.

Where can you access a variable declared in the global scope?

A Only inside the block where it was declared

B Only inside the function where it was declared

C Anywhere in the code

D Nowhere, it is private

Variables declared in the global scope are accessible anywhere in the program.

What happens if you forget to use let, const, or var when declaring a variable inside a function?

A It becomes a global variable

B It causes a syntax error

C It becomes a block-scoped variable

D It is deleted immediately

Without declaration keywords, the variable is created in the global scope, which can cause bugs.

Which object represents the global scope in a browser environment?

A navigator

B document

C console

D window

The window object is the global object in browsers, holding global variables and functions.

How can you keep variables from polluting the global scope?

A Declare them inside functions or blocks using <code>let</code> or <code>const</code>

B Declare them without any keyword

C Declare them only at the top of the file

D Use global variables everywhere

Using let or const inside functions or blocks keeps variables local and avoids global pollution.

Which of these is true about global scope?

A Global scope variables are private to functions

B Variables in global scope can be accessed anywhere

C Global scope variables disappear after a function ends

D Global scope only exists inside blocks

Global scope variables are accessible from any part of the code.

Explain what global scope means in JavaScript and why it can be risky to use too many global variables.

Think about how variables can be seen everywhere and how that might cause problems.

Describe how to avoid polluting the global scope when writing JavaScript code.

Focus on how to keep variables limited to where they are needed.