JavaScript Comments Tutorial
JavaScript comments are annotations that can be added to code to make it more readable and understandable. They are ignored by the JavaScript engine when the code is executed.
There are two types of comments in JavaScript:
Single-line comments: Start with two forward slashes (//) and continue to the end of the line.
Multi-line comments: Start with /* and end with */. Everything between the start and end markers is considered a comment.
Single-line comments are typically used to add short notes or explanations to code. For example:
// This is a single-line comment.const myVariable = 10;
Multi-line comments are typically used to add longer explanations or to disable code that is not currently needed. For example:
/* This is a multi-line comment. It can be used to add longer explanations or to disable code. */console.log("This code will not be executed.");// This code will be executed.
console.log("This code will be executed.");
Here are some tips for writing effective JavaScript comments:
Use comments to explain what your code is doing, not how it is doing it.
Be specific and concise.
Use comments to document any assumptions or limitations of your code.
Keep your comments up to date.
Here are some examples of good JavaScript comments:
// This function calculates the sum of two numbers.function add(a, b) {
return a + b;
}// This variable stores the current user’s name.
const userName = "Bard";// This code disables the save button until the user has entered a valid name.
if (userName === "") {// Disable the save button.
document.getElementById("saveButton").disabled = true;
} else {// Enable the save button.
document.getElementById("saveButton").disabled = false;
}
Comments are an important part of writing good JavaScript code. By using comments effectively, you can make your code more readable, maintainable, and understandable by yourself and other developers.