Câu 1: Which keyword is used to declare a block-scoped variable in JavaScript?

var let const static

Câu 2: Which keyword declares a constant that cannot be reassigned?

var let const final

Câu 3: Which operator compares both value and data type?

== = === !=

Câu 4: What is the result of the expression: 5 + '5'?

10 55 NaN Error

Câu 5: Which operator is used to get the remainder of a division?

/ % // mod

Câu 6: What is the boolean value of the expression: !true?

true false undefined

Câu 7: Which statement is used to execute code when a condition is true?

for while if switch

Câu 8: Which block runs when the if condition is false?

then default catch else

Câu 9: Which structure is suitable when there are multiple branches based on specific values?

if else if switch for

Câu 10: Which keyword is used to exit a case in a switch statement?

exit stop break return

Câu 11: Which keyword marks the default block in a switch statement?

else default finally otherwise

Câu 12: Which loop runs while a condition remains true?

for foreach loop repeat

Câu 13: How many main parts are in the for loop syntax?

2 3 4 5

Câu 14: Which loop checks the condition before executing the code block?

do...while forEach while map

Câu 15: Which loop executes at least once even if the condition is false?

while for loop do...while

Câu 16: Which keyword skips the current iteration and continues the loop?

skip continue pass next

Câu 17: Which keyword completely exits a loop?

exit break stop return

Câu 18: What is the index of the first element in an array?

1 -1 0

Câu 19: How do you access the second element of an array named arr?

arr(2) arr[2] arr[1] arr.second

Câu 20: Which property returns the number of elements in an array?

size count length index

Câu 21: Which method adds an element to the end of an array?

push() pop() shift() unshift()

Câu 22: Which method removes the last element of an array?

push() pop() slice() concat()

Câu 23: Which method adds an element to the beginning of an array?

push() append() unshift() insert()

Câu 24: Which method removes the first element of an array?

shift() pop() remove() delete()

Câu 25: Which keyword is used to declare a function in JavaScript?

func def function method

Câu 26: How do you declare a function named sum?

function = sum() create sum() function sum() def sum()

Câu 27: Where are function parameters placed?

In square brackets [] In parentheses () In curly braces {} After the return keyword

Câu 28: Which keyword specifies the return value of a function?

result yield return output

Câu 29: If a function has no return statement, what is the default return value?

0 false undefined

Câu 30: How can a function be called?

functionName[] functionName{} functionName() call functionName

Câu 31: Who developed the first version of JavaScript at Netscape in 1995?

James Gosling Brendan Eich Tim Berners-Lee Guido van Rossum

Câu 32: Which edition of ECMAScript introduced 'strict mode' and JSON support?

ECMAScript 3 ECMAScript 2015 ECMAScript 5 ECMAScript 6

Câu 33: Where is Client-side JavaScript (CSJS) executed?

On the Web server In the database engine On a remote cloud proxy In the browser on the user's workstation

Câu 34: What is the process of converting server-side JavaScript code into machine-independent bytecode called?

Interpretation Compilation Encryption Serialization

Câu 35: Which HTML tag is used to define a script to make pages interactive?

Câu 36: In JavaScript, which keyword is used to create a variable by allocating memory to it?

var dim set new

Câu 37: Which primitive data type in JavaScript contains only two values: true or false?

number string boolean

Câu 38: What does a 'null' value in a variable specify?

The variable has the value zero The variable has no value The variable contains an empty string The variable is undefined

Câu 39: Which of the following is classified as a composite data type in JavaScript?

String Number Arrays Boolean

Câu 40: Which method of the document object displays data and appends a new line character?

write() writeln() print() alert()

Tính giai thừa N! trong Javascript

[Trắc Nghiệm] Ôn tập kiến thức javascript & luyện thi & phỏng vấn

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