JavaScript Worksheet: Basics

HTML and CSS lesson 25: JavaScript basics · Set 866 · 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 runs = 8;
   runs = runs + 18;
   runs = runs - 15;
   console.log(runs);
2. 2.⚡ A JavaScript file usually ends with which extension? (a) .jpg (b) .css (c) .js (d) .html
3. 3.⚡ 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
4. 4.⚡ What does this code print? (Look at the quotes!)
   let x = "5";
   let y = 9;
   console.log(x + y); (a) Error (b) 14 (c) 59
5. 5.⚡ Which tag holds JavaScript in a page? (a) <script> (b) <js> (c) <style> (d) <code>
6. 6.⚡ Which JavaScript word writes in the console? (a) for (b) let (c) if (d) console.log()
7. 7.⚡ What does this code print? (Look at the quotes!)
   let x = "5";
   let y = 4;
   console.log(x + y); (a) Error (b) 54 (c) 9
8. 8.⚡ Which word makes a new variable? (a) make (b) give (c) put (d) let
9. 9.⚡ Which JavaScript word makes a new variable? (a) alert() (b) let (c) for (d) console.log()
10. 10.⚡ What does this code print? (Look at the quotes!)
    let x = "3";
    let y = 6;
    console.log(x + y); (a) 9 (b) Error (c) 36
11. 11.⚡ What does JavaScript add to a web page? (a) the domain name (b) the page title (c) actions and changes (d) only colours
12. 12.⚡ Which JavaScript word repeats code? (a) if (b) alert() (c) for (d) let
13. 13.⚡ What number does this code print?
    let a = 32;
    let b = 23;
    console.log(a - b);
14. 14.⚡ What number does this code print?
    let score = 25;
    score = score + 16;
    score = score - 4;
    console.log(score);
15. 15.⚡ What number does this code print?
    let a = 35;
    let b = 33;
    console.log(a - b);
16. 16.⚡ What number does this code print?
    let marks = 29;
    marks = marks + 3;
    marks = marks - 8;
    console.log(marks);
17. 17.⚡ What does this code print? (Look at the quotes!)
    let x = "9";
    let y = 2;
    console.log(x + y); (a) 11 (b) Error (c) 92
18. 18.⚡ What does this code print? (Look at the quotes!)
    let x = "3";
    let y = 7;
    console.log(x + y); (a) 10 (b) Error (c) 37
19. 19.⚡ What does this code print? (Look at the quotes!)
    let x = "7";
    let y = 4;
    console.log(x + y); (a) Error (b) 74 (c) 11
20. 20.⚡ Which JavaScript word shows a pop-up box? (a) if (b) alert() (c) for (d) console.log()
21. 21.⚡ What number does this code print?
    let a = 30;
    let b = 16;
    console.log(a - b);
22. 22.⚡ What does this code print? (Look at the quotes!)
    let x = "6";
    let y = 2;
    console.log(x + y); (a) 62 (b) Error (c) 8
23. 23.⚡ 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
24. 24.⚡ What does this code show?
    let name = "Meera";
    console.log("Welcome, " + name + "!"); (a) Meera (b) Welcome, Meera! (c) Welcome, name! (d) name
25. 25.⚡ What does alert() show? (a) a picture (b) a new tab (c) a pop-up box (d) a table
26. 26.⚡ What does this code print? (Look at the quotes!)
    let x = "6";
    let y = 4;
    console.log(x + y); (a) 64 (b) 10 (c) Error
27. 27.⚡ What does this code print? (Look at the quotes!)
    let x = "5";
    let y = 7;
    console.log(x + y); (a) 12 (b) 57 (c) Error
28. 28.⚡ Which JavaScript word runs code when true? (a) console.log() (b) let (c) if (d) for
29. 29.⚡ What does this code show?
    let name = "Aman";
    alert("Well done, " + name + "!"); (a) name (b) Aman (c) Well done, Aman! (d) Well done, name!
30. 30.⚡ Where does console.log() show its output? (a) on the title bar (b) on the printer (c) in the console (d) in the address bar
31. 31.⚡ What does this code show?
    let name = "Zoya";
    console.log("Well done, " + name + "!"); (a) Zoya (b) Well done, name! (c) Well done, Zoya! (d) name
32. 32.⚡ What number does this code print?
    let apples = 25;
    apples = apples + 19;
    apples = apples - 13;
    console.log(apples);
33. 33.⚡ What number does this code print?
    let a = 21;
    let b = 23;
    console.log(a + b);
34. 34.⚡ What does this code show?
    let name = "Zoya";
    console.log("Hi, " + name + "!"); (a) Hi, Zoya! (b) Hi, name! (c) name (d) Zoya
35. 35.⚡ What does this code show?
    let name = "Zoya";
    alert("Welcome, " + name + "!"); (a) Welcome, Zoya! (b) Welcome, name! (c) name (d) Zoya
36. 36.⚡ What number does this code print?
    let a = 26;
    let b = 8;
    console.log(a - b);
37. 37.⚡ What does this code print? (Look at the quotes!)
    let x = "3";
    let y = 2;
    console.log(x + y); (a) Error (b) 5 (c) 32
38. 38.⚡ What number does this code print?
    let a = 3;
    let b = 6;
    console.log(a * b);
39. 39.⚡ What number does this code print?
    let apples = 20;
    apples = apples + 17;
    apples = apples - 2;
    console.log(apples);
40. 40.⚡ What does this code print? (Look at the quotes!)
    let x = "8";
    let y = 3;
    console.log(x + y); (a) Error (b) 11 (c) 83

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