JavaScript Worksheet: Basics

HTML and CSS lesson 25: JavaScript basics · Set 459 · 40 questions

Code tip (Line by line): let x = 5; makes a variable x holding 5; x = x + 2; changes it to 7. console.log(…) writes in the console; alert(…) shows a pop-up box. Text in quotes + anything = joined text: "5" + 3 → "53".

1. 1.⚡ Where does console.log() show its output? (a) on the printer (b) on the title bar (c) in the address bar (d) in the console
2. 2.⚡ Which word makes a new variable? (a) make (b) let (c) give (d) put
3. 3.⚡ What does this code print? (Look at the quotes!)
   let x = "2";
   let y = 4;
   console.log(x + y); (a) 6 (b) 24 (c) Error
4. 4.⚡ Which JavaScript word makes a new variable? (a) alert() (b) let (c) if (d) for
5. 5.⚡ What number does this code print?
   let marks = 8;
   marks = marks + 2;
   marks = marks - 8;
   console.log(marks);
6. 6.⚡ What number does this code print?
   let a = 37;
   let b = 9;
   console.log(a + b);
7. 7.⚡ What number does this code print?
   let a = 39;
   let b = 12;
   console.log(a - b);
8. 8.⚡ Which JavaScript word runs code when true? (a) if (b) console.log() (c) for (d) let
9. 9.⚡ What number does this code print?
   let a = 48;
   let b = 29;
   console.log(a + b);
10. 10.⚡ Which tag holds JavaScript in a page? (a) <code> (b) <js> (c) <script> (d) <style>
11. 11.⚡ What does this code show?
    let name = "Aman";
    alert("Welcome, " + name + "!"); (a) Aman (b) Welcome, name! (c) name (d) Welcome, Aman!
12. 12.⚡ What does this code show?
    let name = "Kabir";
    alert("Hello, " + name + "!"); (a) name (b) Hello, Kabir! (c) Hello, name! (d) Kabir
13. 13.⚡ Which JavaScript word repeats code? (a) alert() (b) let (c) for (d) if
14. 14.⚡ What does this code print? (Look at the quotes!)
    let x = "1";
    let y = 3;
    console.log(x + y); (a) 4 (b) 13 (c) Error
15. 15.⚡ What does this code show?
    let name = "Aman";
    console.log("Hello, " + name + "!"); (a) name (b) Hello, Aman! (c) Hello, name! (d) Aman
16. 16.⚡ Which JavaScript word shows a pop-up box? (a) console.log() (b) for (c) let (d) alert()
17. 17.⚡ A JavaScript file usually ends with which extension? (a) .css (b) .js (c) .html (d) .jpg
18. 18.⚡ What does this code print? (Look at the quotes!)
    let x = "6";
    let y = 2;
    console.log(x + y); (a) 8 (b) 62 (c) Error
19. 19.⚡ What number does this code print?
    let a = 21;
    let b = 6;
    console.log(a - b);
20. 20.⚡ Which JavaScript word writes in the console? (a) alert() (b) let (c) if (d) console.log()
21. 21.⚡ What does this code show?
    let name = "Arjun";
    console.log("Hi, " + name + "!"); (a) Hi, Arjun! (b) Hi, name! (c) name (d) Arjun
22. 22.⚡ What does this code print? (Look at the quotes!)
    let x = "9";
    let y = 1;
    console.log(x + y); (a) 10 (b) 91 (c) Error
23. 23.⚡ What number does this code print?
    let a = 2;
    let b = 8;
    console.log(a * b);
24. 24.⚡ What number does this code print?
    let marks = 17;
    marks = marks + 13;
    marks = marks - 8;
    console.log(marks);
25. 25.⚡ What does JavaScript add to a web page? (a) only colours (b) the page title (c) actions and changes (d) the domain name
26. 26.⚡ What number does this code print?
    let books = 30;
    books = books + 9;
    books = books - 18;
    console.log(books);
27. 27.⚡ What number does this code print?
    let a = 37;
    let b = 4;
    console.log(a + b);
28. 28.⚡ What number does this code print?
    let a = 7;
    let b = 12;
    console.log(a * b);
29. 29.⚡ What does this code print? (Look at the quotes!)
    let x = "7";
    let y = 5;
    console.log(x + y); (a) Error (b) 12 (c) 75
30. 30.⚡ What number does this code print?
    let books = 23;
    books = books + 12;
    books = books - 9;
    console.log(books);
31. 31.⚡ What does this code print? (Look at the quotes!)
    let x = "7";
    let y = 3;
    console.log(x + y); (a) 10 (b) Error (c) 73
32. 32.⚡ What number does this code print?
    let a = 27;
    let b = 18;
    console.log(a - b);
33. 33.⚡ What number does this code print?
    let a = 28;
    let b = 25;
    console.log(a - b);
34. 34.⚡ What number does this code print?
    let a = 40;
    let b = 13;
    console.log(a - b);
35. 35.⚡ What does this code show?
    let name = "Aman";
    console.log("Well done, " + name + "!"); (a) name (b) Well done, name! (c) Aman (d) Well done, Aman!
36. 36.⚡ What number does this code print?
    let books = 21;
    books = books + 3;
    books = books - 3;
    console.log(books);
37. 37.⚡ What does alert() show? (a) a table (b) a new tab (c) a pop-up box (d) a picture
38. 38.⚡ What does this code print? (Look at the quotes!)
    let x = "9";
    let y = 6;
    console.log(x + y); (a) 96 (b) Error (c) 15
39. 39.⚡ What number does this code print?
    let coins = 22;
    coins = coins + 16;
    coins = coins - 14;
    console.log(coins);
40. 40.⚡ What number does this code print?
    let a = 30;
    let b = 22;
    console.log(a - b);

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