var can create a global variable when declared outside any function. let and const do not create global object properties.
What is the global object in a browser environment?
A). window
B). global
C). document
D). this
What will be the output of console.log(window.myVar); if var myVar = 'Hello'; is declared outside any function?
A). Hello
B). undefined
C). error
D). null
What is the purpose of the global object in JavaScript?
A). To store local variables
B). To provide a namespace for global variables and functions
C). To define constants
D). To execute code in strict mode
What is the output of console.log(globalThis === window); in a browser environment?
A). 1
B). 0
C). undefined
D). null
Which of the following can be used to prevent accidental modification of global variables?
A). Encapsulation
B). Namespace
C). Strict mode
D). Block scoping
Which statement is true about global variables in JavaScript?
A). They are not accessible inside functions
B). They can be accessed and modified from any part of the code
C). They are constants
D). They can only be read, not modified
How can you avoid global scope pollution?
A). By using local variables
B). By using IIFE (Immediately Invoked Function Expressions)
C). By using modules
D). All of the above
Which of the following methods can help in avoiding global variables?
A). Using functions to encapsulate code
B). Using objects to namespace code
C). Using ES6 modules
D). All of the above
How do you declare a global variable inside a function?
A). Using var
B). Using let
C). Using const
D). Assigning to window
What is the output of console.log(globalVar); if globalVar = 'Hello'; is assigned inside a function without using var, let, or const?
A). Hello
B). undefined
C). error
D). null