Which value is automatically assigned to a variable that has not been assigned a value?

a$)$ null

b$)$ undefined

c$)0$

d$){?}^{nnt}$

Which function can we use in JavaScript to request user input

a$)$ alert

b$)$ readlin

c$)$ prompt

d$)$ read

What is the purpose of the trim $0$ method in JavaScript string manipulation?

a$)$ To split a string into an array of substrings

b$)$ To convert a string to uppercase

c$)$ To replace a substring in a string with another substring

d$)$ To remove all whitespace characters from the beginning and end of a string

What is the purpose of the db$.$query function in Node.js database operations?

a$)$ If is used to establish a connection with the database server

b$)$ It is used to execute SQL queries and retrieve data from the database

c$)$ It is used to define the structure and schema of the database

d$)$ It is used to perform data validation and enforce constraints on the database

What is the main advantage of using AJAX in web development?

a$)$ It improves website security

b$)$ Mainly used to optimize website performance

c$)$ It enhances the user experience by allowing data to be loaded dynamically without refreshing the entire page

d$)$ To manage server$-$side database operations

$\frac{5}{12}$