JavaScript Worksheet: Basics

HTML and CSS lesson 25: JavaScript basics · Set 390 · 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 does this code print? (Look at the quotes!)
   let x = "7";
   let y = 1;
   console.log(x + y); (a) 8 (b) Error (c) 71
2. 2.⚡ What number does this code print?
   let a = 24;
   let b = 12;
   console.log(a - b);
3. 3.⚡ What does this code print? (Look at the quotes!)
   let x = "5";
   let y = 4;
   console.log(x + y); (a) 9 (b) 54 (c) Error
4. 4.⚡ Where does console.log() show its output? (a) on the title bar (b) in the console (c) on the printer (d) in the address bar
5. 5.⚡ A JavaScript file usually ends with which extension? (a) .css (b) .js (c) .jpg (d) .html
6. 6.⚡ What does alert() show? (a) a table (b) a pop-up box (c) a picture (d) a new tab
7. 7.⚡ What does this code print? (Look at the quotes!)
   let x = "3";
   let y = 9;
   console.log(x + y); (a) Error (b) 12 (c) 39
8. 8.⚡ What number does this code print?
   let a = 23;
   let b = 34;
   console.log(a + b);
9. 9.⚡ What number does this code print?
   let a = 39;
   let b = 38;
   console.log(a + b);
10. 10.⚡ 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
11. 11.⚡ Which JavaScript word makes a new variable? (a) alert() (b) if (c) let (d) console.log()
12. 12.⚡ What number does this code print?
    let a = 17;
    let b = 28;
    console.log(a + b);
13. 13.⚡ Which JavaScript word shows a pop-up box? (a) for (b) let (c) alert() (d) if
14. 14.⚡ Which JavaScript word repeats code? (a) for (b) if (c) alert() (d) console.log()
15. 15.⚡ What number does this code print?
    let a = 33;
    let b = 25;
    console.log(a + b);
16. 16.⚡ What does this code show?
    let name = "Kabir";
    console.log("Well done, " + name + "!"); (a) Well done, name! (b) name (c) Well done, Kabir! (d) Kabir
17. 17.⚡ What number does this code print?
    let a = 45;
    let b = 24;
    console.log(a + b);
18. 18.⚡ Which word makes a new variable? (a) put (b) make (c) let (d) give
19. 19.⚡ What number does this code print?
    let coins = 17;
    coins = coins + 15;
    coins = coins - 16;
    console.log(coins);
20. 20.⚡ What number does this code print?
    let books = 5;
    books = books + 3;
    books = books - 7;
    console.log(books);
21. 21.⚡ 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
22. 22.⚡ What number does this code print?
    let a = 44;
    let b = 10;
    console.log(a + b);
23. 23.⚡ What number does this code print?
    let a = 47;
    let b = 5;
    console.log(a - b);
24. 24.⚡ What does this code print? (Look at the quotes!)
    let x = "8";
    let y = 5;
    console.log(x + y); (a) 13 (b) Error (c) 85
25. 25.⚡ What does this code print? (Look at the quotes!)
    let x = "1";
    let y = 9;
    console.log(x + y); (a) 19 (b) Error (c) 10
26. 26.⚡ What does this code print? (Look at the quotes!)
    let x = "9";
    let y = 4;
    console.log(x + y); (a) 13 (b) Error (c) 94
27. 27.⚡ What number does this code print?
    let a = 20;
    let b = 12;
    console.log(a + b);
28. 28.⚡ What number does this code print?
    let a = 12;
    let b = 4;
    console.log(a * b);
29. 29.⚡ What number does this code print?
    let a = 3;
    let b = 10;
    console.log(a * b);
30. 30.⚡ Which JavaScript word writes in the console? (a) alert() (b) console.log() (c) let (d) for
31. 31.⚡ What number does this code print?
    let runs = 5;
    runs = runs + 17;
    runs = runs - 17;
    console.log(runs);
32. 32.⚡ What number does this code print?
    let marks = 14;
    marks = marks + 19;
    marks = marks - 6;
    console.log(marks);
33. 33.⚡ What does this code print? (Look at the quotes!)
    let x = "4";
    let y = 5;
    console.log(x + y); (a) Error (b) 9 (c) 45
34. 34.⚡ What does this code show?
    let name = "Arjun";
    console.log("Well done, " + name + "!"); (a) name (b) Arjun (c) Well done, Arjun! (d) Well done, name!
35. 35.⚡ What number does this code print?
    let score = 11;
    score = score + 4;
    score = score - 14;
    console.log(score);
36. 36.⚡ Which JavaScript word runs code when true? (a) alert() (b) console.log() (c) for (d) if
37. 37.⚡ What number does this code print?
    let a = 3;
    let b = 2;
    console.log(a * b);
38. 38.⚡ Which tag holds JavaScript in a page? (a) <js> (b) <script> (c) <code> (d) <style>
39. 39.⚡ What number does this code print?
    let marks = 19;
    marks = marks + 8;
    marks = marks - 5;
    console.log(marks);
40. 40.⚡ What does JavaScript add to a web page? (a) the page title (b) the domain name (c) only colours (d) actions and changes

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