What is JavaScript?

JavaScript (JS) is more than just a mark-up language like HTML. JavaScript is a scripting language used by web developers to write complex instructions for a website to enable extended functionality and design features.

JS is similar to PHP in the way that it is a scripting language; however it is important to note that JS is a client side scripting language, whereas PHP is server side. This means that although JS can be used for more complex scripting, it is limited in its security and its application. JavaScript used on a website is easily viewed by any user which means the instructions and any information contained within the JavaScript itself can be read.

Although JavaScript does have limitations in application it (and its associated libraries) is widely adopted as the language of choice for web developers looking for a quick and easy way of achieving dynamic like functionality on an HTML/CSS only website.