We differentiate between technologies that are executed on the CLIENT-SIDE (Browser) and on the SERVER-SIDE:
Client-side (browser) executed technologies:
HyperText Markup Language, commonly referred to as HTML, is the standard markup language used to create web pages. Web browsers can read HTML files and render them into visible or audible web pages. HTML describes the structure of a website semantically along with cues for presentation, making it a markup language, rather than a programming language. HTML is executed on the client’s side (browser). (Wikipedia). See HTML intro here.
Cascading Style Sheets (CSS) is a style sheet language used for describing the presentation of a document written in a markup language like HTML (but also others). CSS is designed primarily to enable the separation of document content from document presentation, including aspects such as the layout, colors, and fonts. This separation can improve content accessibility, provide more flexibility and control in the specification of presentation characteristics, enable multiple HTML pages to share formatting by specifying the relevant CSS in a separate .css file, and reduce complexity and repetition in the structural contents. Like HTML, it is also executed on the client side (browser). See CSS intro here.
Extensible Markup Language (XML) is a markup language that defines a set of rules for encoding documents in a format that is both human-readable and machine-readable.
Server-side executed technologies
PHP is a server-side scripting language designed for web development, but also used as a general-purpose programming language. PHP code may be embedded into HTML code, or it can be used in combination with various Web template systems and web frameworks. PHP code is usually processed by a PHP interpreter in the web server. The web server combines the results of the interpreted and executed PHP code, which may be any type of data, including images, with the generated web page. The majority of open source content management systems, like WordPress used ion this website here, are basically written in PHP. The market share is estimated at 75%.
ASP.NET is an open-source server-side web application framework designed for web development to produce dynamic web pages. It was developed by Microsoft to allow programmers to build dynamic web sites, web applications and web services. It still has a relatively high market share (approx. 18%), but is rather unpopular for independent developer’s, since it targets mainly on Companies with Microsoft business applications.
Ruby on Rails