JavaScript

JavaScript (JS) is a high-level, client-side language, meaning that it is like a human language (rather than, for example, binary) and runs on the end user's computer. It is used for many purposes, including editing content on a webpage, performing mathematical operations and storing variables. Each line of JavaScript should end in a semicolon, for example:
// this code sets the content of the element with the ID "id_name" to "Hello World!"
document.getElementById("id_name").innerHTML = "Hello World!";
A single line comment in JS is denoted by a double forward slash (//); a multi line comment is started with /* and ended with */.