Introduction to JavaScript

JavaScript is a high-level programming language that all modern web browsers support. It is also one of the core technologies of the web, along with HTML and CSS that you may have learned previously. This section will cover basic JavaScript programming concepts, which range from variables and arithmetic to objects and loops.

 

Usage

Comments are lines of code that JavaScript will intentionally ignore. Comments are a great way to leave notes to yourself and to other people who will later need to figure out what that code does.

There are two ways to write comments in JavaScript:

Using // will tell JavaScript to ignore the remainder of the text on the current line:

// This is an in-line comment.

You can make a multi-line comment beginning with /* and ending with */

/* This is a
multi-line comment. */

 

Best Practice

As you write code, you should regularly add comments to clarify the function of parts of your code. Good commenting can help communicate the intent of your code—both for others and for your future self.