JavaScript Worksheet: Basics

HTML and CSS lesson 25: JavaScript basics · Set 388 · 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) .js (b) .css (c) .jpg (d) .html
2. 2.⚡ What does this code print? (Look at the quotes!)
   let x = "7";
   let y = 8;
   console.log(x + y); (a) 78 (b) 15 (c) Error
3. 3.⚡ What does this code print? (Look at the quotes!)
   let x = "6";
   let y = 5;
   console.log(x + y); (a) 65 (b) Error (c) 11
4. 4.⚡ What does this code print? (Look at the quotes!)
   let x = "1";
   let y = 3;
   console.log(x + y); (a) Error (b) 4 (c) 13
5. 5.⚡ What number does this code print?
   let a = 37;
   let b = 30;
   console.log(a + b);
6. 6.⚡ What does this code print? (Look at the quotes!)
   let x = "9";
   let y = 9;
   console.log(x + y); (a) 18 (b) 99 (c) Error
7. 7.⚡ Where does console.log() show its output? (a) on the printer (b) in the address bar (c) on the title bar (d) in the console
8. 8.⚡ Which tag holds JavaScript in a page? (a) <script> (b) <js> (c) <style> (d) <code>
9. 9.⚡ What does JavaScript add to a web page? (a) actions and changes (b) the page title (c) the domain name (d) only colours
10. 10.⚡ What does alert() show? (a) a new tab (b) a table (c) a picture (d) a pop-up box
11. 11.⚡ What number does this code print?
    let score = 28;
    score = score + 13;
    score = score - 21;
    console.log(score);
12. 12.⚡ What does this code print? (Look at the quotes!)
    let x = "3";
    let y = 7;
    console.log(x + y); (a) 10 (b) 37 (c) Error
13. 13.⚡ What number does this code print?
    let a = 11;
    let b = 11;
    console.log(a + b);
14. 14.⚡ What does this code show?
    let name = "Riya";
    alert("Welcome, " + name + "!"); (a) Welcome, Riya! (b) Welcome, name! (c) name (d) Riya
15. 15.⚡ Which word makes a new variable? (a) give (b) make (c) let (d) put
16. 16.⚡ What number does this code print?
    let a = 55;
    let b = 11;
    console.log(a - b);
17. 17.⚡ What does this code print? (Look at the quotes!)
    let x = "2";
    let y = 2;
    console.log(x + y); (a) 22 (b) Error (c) 4
18. 18.⚡ What number does this code print?
    let marks = 14;
    marks = marks + 14;
    marks = marks - 6;
    console.log(marks);
19. 19.⚡ What number does this code print?
    let a = 20;
    let b = 9;
    console.log(a - b);
20. 20.⚡ What number does this code print?
    let a = 41;
    let b = 14;
    console.log(a + b);
21. 21.⚡ What number does this code print?
    let coins = 29;
    coins = coins + 6;
    coins = coins - 1;
    console.log(coins);
22. 22.⚡ What number does this code print?
    let runs = 27;
    runs = runs + 17;
    runs = runs - 7;
    console.log(runs);
23. 23.⚡ What does this code show?
    let name = "Kabir";
    alert("Hi, " + name + "!"); (a) name (b) Kabir (c) Hi, name! (d) Hi, Kabir!
24. 24.⚡ What does this code print? (Look at the quotes!)
    let x = "8";
    let y = 7;
    console.log(x + y); (a) Error (b) 87 (c) 15
25. 25.⚡ Which JavaScript word shows a pop-up box? (a) let (b) for (c) alert() (d) if
26. 26.⚡ Which JavaScript word makes a new variable? (a) for (b) let (c) console.log() (d) alert()
27. 27.⚡ Which JavaScript word repeats code? (a) console.log() (b) for (c) if (d) alert()
28. 28.⚡ What number does this code print?
    let a = 2;
    let b = 9;
    console.log(a * b);
29. 29.⚡ What does this code print? (Look at the quotes!)
    let x = "3";
    let y = 6;
    console.log(x + y); (a) Error (b) 9 (c) 36
30. 30.⚡ What does this code print? (Look at the quotes!)
    let x = "1";
    let y = 4;
    console.log(x + y); (a) Error (b) 14 (c) 5
31. 31.⚡ What number does this code print?
    let runs = 6;
    runs = runs + 14;
    runs = runs - 9;
    console.log(runs);
32. 32.⚡ What number does this code print?
    let a = 5;
    let b = 12;
    console.log(a * b);
33. 33.⚡ Which JavaScript word runs code when true? (a) if (b) let (c) for (d) alert()
34. 34.⚡ What number does this code print?
    let a = 4;
    let b = 5;
    console.log(a * b);
35. 35.⚡ 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
36. 36.⚡ What number does this code print?
    let a = 24;
    let b = 9;
    console.log(a + b);
37. 37.⚡ 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
38. 38.⚡ What does this code show?
    let name = "Riya";
    console.log("Hello, " + name + "!"); (a) Hello, name! (b) Riya (c) name (d) Hello, Riya!
39. 39.⚡ What number does this code print?
    let books = 9;
    books = books + 18;
    books = books - 17;
    console.log(books);
40. 40.⚡ What does this code print? (Look at the quotes!)
    let x = "6";
    let y = 7;
    console.log(x + y); (a) Error (b) 13 (c) 67

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