Comments
Part of the Fundamentals section of Coddy's JavaScript journey — lesson 3 of 77.
Comments are notes you write inside your code. JavaScript completely ignores them - they exist only to help humans understand the code.
To write a single-line comment, use //. Everything after // until the end of the line is ignored:
// This is a comment
console.log("Hello!")A comment can also be written at the end of a line, after the code:
console.log("Hello!") // This prints Hello!For comments that span several lines, use /* to start and */ to end:
/* This is a multi-line comment.
JavaScript ignores all of it. */
console.log("Welcome!")Comments can also temporarily disable a line of code without deleting it:
// console.log("This line will NOT run")
console.log("This line will run")Note: Every multi-line comment that starts with /* must be closed with */, otherwise JavaScript treats everything after it as a comment.
Challenge
BeginnerFix the code so that only Hello, JavaScript! is printed.
- Replace the
?with the symbols that turn a line into a comment - The line printing
Goodbye!should become a comment so it does NOT run - Only change the line that starts with
?
Try it yourself
// Type your code below
? console.log("Goodbye!")
console.log("Hello, JavaScript!")
Test yourselfThis lesson includes a short quiz. Start the lesson to answer it and track your progress.
All lessons in Fundamentals
4Operators Part 2
Logical Operators Part 1Logical Operators Part 2Recap - Simple LogicLogical Operators Part 3Type Coercion7Bill Split Calculator
Welcome MessageCalculating The Tip And Total
Splitting The BillFormatted Output2Variables
NumbersStringBooleanNaming ConventionsEmpty VariablesRecap - Initialize VariablesConstants3Operators Part 1
Arithmetic OperatorsModulo OperatorArithmetic ShortcutsComparison OperatorsStrict vs Loose EqualityRecap - Simple Math6Basic IO
OutputOutput with VariablesType Conversion - Part 1Type Conversion - Part 2Recap - Till 120Recap - True or False