Answer & Solution
var can create a global variable when declared outside any function. let and const do not create global object properties.
var can create a global variable when declared outside any function. let and const do not create global object properties.
What happens if you declare a variable without var, let, or const inside a function?
A). It becomes a global variable
B). It becomes a local variable
C). It throws an error
D). It becomes a constant
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
What is the output of console.log(globalThis === window); in a browser environment?
A). 1
B). 0
C). undefined
D). null
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
What is the output of typeof window in a browser environment?
A). object
B). undefined
C). function
D). global
How can you access a global variable inside a function if it has the same name as a local variable?
A). By using the window object
B). By using the global object
C). By using a different name for the global variable
D). By using the this keyword
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
Which of the following can be used to prevent accidental modification of global variables?
A). Encapsulation
B). Namespace
C). Strict mode
D). Block scoping
Can a global variable be accessed inside a function?
A). Yes
B). No
C). Only if passed as a parameter
D). Only if defined with var
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