JavaScript Worksheet: Basics

HTML and CSS lesson 25: JavaScript basics · Set 51 · 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.⚡ What number does this code print?
   let a = 23;
   let b = 11;
   console.log(a + b);
2. 2.⚡ Which JavaScript word runs code when true? (a) alert() (b) if (c) for (d) let
3. 3.⚡ What does this code print? (Look at the quotes!)
   let x = "2";
   let y = 8;
   console.log(x + y); (a) Error (b) 28 (c) 10
4. 4.⚡ A JavaScript file usually ends with which extension? (a) .css (b) .jpg (c) .js (d) .html
5. 5.⚡ What does this code print? (Look at the quotes!)
   let x = "2";
   let y = 3;
   console.log(x + y); (a) 5 (b) Error (c) 23
6. 6.⚡ Which JavaScript word writes in the console? (a) if (b) alert() (c) console.log() (d) let
7. 7.⚡ Which JavaScript word shows a pop-up box? (a) let (b) console.log() (c) for (d) alert()
8. 8.⚡ Which tag holds JavaScript in a page? (a) <style> (b) <code> (c) <js> (d) <script>
9. 9.⚡ Which JavaScript word makes a new variable? (a) alert() (b) console.log() (c) for (d) let
10. 10.⚡ What does this code print? (Look at the quotes!)
    let x = "3";
    let y = 5;
    console.log(x + y); (a) Error (b) 8 (c) 35
11. 11.⚡ What number does this code print?
    let books = 17;
    books = books + 17;
    books = books - 33;
    console.log(books);
12. 12.⚡ What does this code print? (Look at the quotes!)
    let x = "1";
    let y = 6;
    console.log(x + y); (a) Error (b) 16 (c) 7
13. 13.⚡ 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
14. 14.⚡ What number does this code print?
    let a = 37;
    let b = 17;
    console.log(a - b);
15. 15.⚡ What number does this code print?
    let a = 41;
    let b = 36;
    console.log(a + b);
16. 16.⚡ 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
17. 17.⚡ What does this code print? (Look at the quotes!)
    let x = "7";
    let y = 2;
    console.log(x + y); (a) 72 (b) 9 (c) Error
18. 18.⚡ What number does this code print?
    let a = 2;
    let b = 5;
    console.log(a * b);
19. 19.⚡ What number does this code print?
    let apples = 27;
    apples = apples + 7;
    apples = apples - 30;
    console.log(apples);
20. 20.⚡ What number does this code print?
    let marks = 16;
    marks = marks + 2;
    marks = marks - 6;
    console.log(marks);
21. 21.⚡ What does this code print? (Look at the quotes!)
    let x = "5";
    let y = 3;
    console.log(x + y); (a) 8 (b) 53 (c) Error
22. 22.⚡ What does this code show?
    let name = "Meera";
    alert("Hello, " + name + "!"); (a) Meera (b) name (c) Hello, Meera! (d) Hello, name!
23. 23.⚡ What does this code show?
    let name = "Riya";
    alert("Hi, " + name + "!"); (a) Riya (b) Hi, name! (c) name (d) Hi, Riya!
24. 24.⚡ What does this code show?
    let name = "Zoya";
    console.log("Hi, " + name + "!"); (a) name (b) Hi, Zoya! (c) Hi, name! (d) Zoya
25. 25.⚡ What number does this code print?
    let apples = 13;
    apples = apples + 2;
    apples = apples - 3;
    console.log(apples);
26. 26.⚡ Which word makes a new variable? (a) let (b) put (c) make (d) give
27. 27.⚡ What number does this code print?
    let a = 34;
    let b = 20;
    console.log(a + b);
28. 28.⚡ What number does this code print?
    let a = 7;
    let b = 2;
    console.log(a * b);
29. 29.⚡ What does this code show?
    let name = "Zoya";
    console.log("Well done, " + name + "!"); (a) name (b) Zoya (c) Well done, Zoya! (d) Well done, name!
30. 30.⚡ What number does this code print?
    let a = 12;
    let b = 11;
    console.log(a * b);
31. 31.⚡ What does JavaScript add to a web page? (a) the page title (b) only colours (c) the domain name (d) actions and changes
32. 32.⚡ Which JavaScript word repeats code? (a) if (b) alert() (c) let (d) for
33. 33.⚡ What does this code print? (Look at the quotes!)
    let x = "8";
    let y = 6;
    console.log(x + y); (a) 86 (b) 14 (c) Error
34. 34.⚡ What does this code print? (Look at the quotes!)
    let x = "1";
    let y = 1;
    console.log(x + y); (a) 11 (b) 2 (c) Error
35. 35.⚡ What does this code show?
    let name = "Riya";
    console.log("Well done, " + name + "!"); (a) Well done, name! (b) name (c) Riya (d) Well done, Riya!
36. 36.⚡ What does alert() show? (a) a new tab (b) a picture (c) a table (d) a pop-up box
37. 37.⚡ What number does this code print?
    let a = 26;
    let b = 30;
    console.log(a + b);
38. 38.⚡ What does this code print? (Look at the quotes!)
    let x = "1";
    let y = 5;
    console.log(x + y); (a) 6 (b) Error (c) 15
39. 39.⚡ What does this code show?
    let name = "Kabir";
    alert("Welcome, " + name + "!"); (a) Kabir (b) Welcome, name! (c) Welcome, Kabir! (d) name
40. 40.⚡ What does this code print? (Look at the quotes!)
    let x = "2";
    let y = 4;
    console.log(x + y); (a) 24 (b) 6 (c) Error

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