HTML
HTML (HyperText Markup Language) is the code that is used to structure a web page and its content. For example, content could be structured within a set of paragraphs, a list of bulleted points, or using images and data tables.
CSS
CSS (Cascading Style Sheets) is used to style and layout web pages — for example, to alter the font, color, size, and spacing of your content, split it into multiple columns, or add animations and other decorative features.
JavaScript
JavaScript is a scripting language that enables you to create dynamically updating content, control multimedia, animate images, and pretty much everything else.(Okay, not everything, but it is amazing what you can achieve with a few lines of JavaScript code)