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JavaScript Comments — exercises and bug fixes

5 hands-on exercises and 5 find-the-bug challenges for the JavaScript Comments lesson. Every one is checked automatically in the browser — write the code, run it, and the tests tell you what still fails.

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Exercises(5)

  1. 1

    Add a line comment

    easy10 min

    Explain the line with a // comment, then show "documented".

  2. 2

    Use a block comment

    easy10 min

    Add a /* */ comment above the code, then show "blocked".

  3. 3

    Comment out a line

    easy10 min

    Disable the wrong line with a comment so "correct" is shown.

  4. 4

    Comment at the end of a line

    easy10 min

    Add a trailing comment after the statement.

  5. 5

    Keep code readable

    medium10 min

    Explain a calculation with a comment and show "clear".

Find the bug(5)

  1. 1

    Fix the unclosed block comment

    easy8 min

    The block comment never closes, so the real code is swallowed.

  2. 2

    Fix the commented-out code

    easy8 min

    The working line was accidentally commented out.

  3. 3

    Fix the wrong comment marker

    easy8 min

    A hash is not a JavaScript comment.

  4. 4

    Fix the comment that hides half a line

    easy8 min

    The comment starts too early and disables the assignment.

  5. 5

    Fix the nested block comment

    easy8 min

    Block comments cannot nest, so this breaks.

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