JavaScript Worksheet: Basics

HTML and CSS lesson 25: JavaScript basics · Set 10 · 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.⚡ A JavaScript file usually ends with which extension? (a) .html (b) .js (c) .jpg (d) .css
2. 2.⚡ What number does this code print?
   let a = 34;
   let b = 14;
   console.log(a - b);
3. 3.⚡ What does this code show?
   let name = "Meera";
   alert("Hello, " + name + "!"); (a) Meera (b) Hello, name! (c) name (d) Hello, Meera!
4. 4.⚡ Which JavaScript word runs code when true? (a) console.log() (b) for (c) if (d) let
5. 5.⚡ What does this code print? (Look at the quotes!)
   let x = "9";
   let y = 2;
   console.log(x + y); (a) Error (b) 11 (c) 92
6. 6.⚡ What does this code show?
   let name = "Kabir";
   alert("Hello, " + name + "!"); (a) Kabir (b) Hello, Kabir! (c) Hello, name! (d) name
7. 7.⚡ What number does this code print?
   let books = 25;
   books = books + 5;
   books = books - 5;
   console.log(books);
8. 8.⚡ What does JavaScript add to a web page? (a) the domain name (b) the page title (c) only colours (d) actions and changes
9. 9.⚡ Which JavaScript word writes in the console? (a) alert() (b) console.log() (c) let (d) if
10. 10.⚡ What does this code print? (Look at the quotes!)
    let x = "2";
    let y = 5;
    console.log(x + y); (a) 7 (b) 25 (c) Error
11. 11.⚡ Which tag holds JavaScript in a page? (a) <code> (b) <js> (c) <style> (d) <script>
12. 12.⚡ What does this code show?
    let name = "Kabir";
    console.log("Well done, " + name + "!"); (a) name (b) Kabir (c) Well done, name! (d) Well done, Kabir!
13. 13.⚡ What does this code print? (Look at the quotes!)
    let x = "2";
    let y = 9;
    console.log(x + y); (a) 29 (b) Error (c) 11
14. 14.⚡ What number does this code print?
    let a = 11;
    let b = 11;
    console.log(a * b);
15. 15.⚡ Where does console.log() show its output? (a) on the title bar (b) on the printer (c) in the address bar (d) in the console
16. 16.⚡ What does alert() show? (a) a new tab (b) a picture (c) a table (d) a pop-up box
17. 17.⚡ What does this code print? (Look at the quotes!)
    let x = "6";
    let y = 8;
    console.log(x + y); (a) 68 (b) Error (c) 14
18. 18.⚡ What number does this code print?
    let a = 38;
    let b = 28;
    console.log(a + b);
19. 19.⚡ What does this code print? (Look at the quotes!)
    let x = "3";
    let y = 9;
    console.log(x + y); (a) Error (b) 39 (c) 12
20. 20.⚡ What number does this code print?
    let a = 49;
    let b = 23;
    console.log(a - b);
21. 21.⚡ What number does this code print?
    let a = 8;
    let b = 8;
    console.log(a * b);
22. 22.⚡ What number does this code print?
    let a = 10;
    let b = 4;
    console.log(a * b);
23. 23.⚡ What does this code print? (Look at the quotes!)
    let x = "2";
    let y = 1;
    console.log(x + y); (a) 3 (b) Error (c) 21
24. 24.⚡ Which JavaScript word shows a pop-up box? (a) console.log() (b) alert() (c) if (d) for
25. 25.⚡ What number does this code print?
    let a = 9;
    let b = 25;
    console.log(a + b);
26. 26.⚡ What number does this code print?
    let a = 37;
    let b = 37;
    console.log(a + b);
27. 27.⚡ What number does this code print?
    let a = 56;
    let b = 8;
    console.log(a - b);
28. 28.⚡ What number does this code print?
    let a = 28;
    let b = 4;
    console.log(a - b);
29. 29.⚡ What does this code show?
    let name = "Aman";
    alert("Well done, " + name + "!"); (a) Well done, Aman! (b) Well done, name! (c) name (d) Aman
30. 30.⚡ What number does this code print?
    let apples = 13;
    apples = apples + 16;
    apples = apples - 22;
    console.log(apples);
31. 31.⚡ What does this code print? (Look at the quotes!)
    let x = "3";
    let y = 2;
    console.log(x + y); (a) Error (b) 32 (c) 5
32. 32.⚡ What number does this code print?
    let a = 45;
    let b = 3;
    console.log(a - b);
33. 33.⚡ What does this code print? (Look at the quotes!)
    let x = "3";
    let y = 8;
    console.log(x + y); (a) 11 (b) Error (c) 38
34. 34.⚡ Which JavaScript word repeats code? (a) for (b) console.log() (c) alert() (d) if
35. 35.⚡ Which JavaScript word makes a new variable? (a) let (b) for (c) alert() (d) if
36. 36.⚡ What number does this code print?
    let score = 23;
    score = score + 19;
    score = score - 13;
    console.log(score);
37. 37.⚡ What number does this code print?
    let score = 27;
    score = score + 12;
    score = score - 19;
    console.log(score);
38. 38.⚡ What does this code print? (Look at the quotes!)
    let x = "4";
    let y = 6;
    console.log(x + y); (a) 10 (b) Error (c) 46
39. 39.⚡ What number does this code print?
    let books = 15;
    books = books + 19;
    books = books - 14;
    console.log(books);
40. 40.⚡ What does this code print? (Look at the quotes!)
    let x = "1";
    let y = 2;
    console.log(x + y); (a) 3 (b) Error (c) 12

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