HTML and CSS

The concept of layout and web design with HTML and CSS, and the technologies that go with them.

HTML (the hypertext markup language) and CSS (cascading style sheets) are two of the core technologies for building web pages. HTML provides the page's *structure*; CSS, the (visual and auditory) *layout* for a variety of devices. Together with graphics and scripts, HTML and CSS are the foundation for building web pages and applications.

What is HTML?

HTML is the language for describing the structure of web pages. HTML gives authors the means to:

Publish documents online with headings, text, tables, lists, photos, etc.
Design forms to carry out transactions with remote services: search for information, make reservations, order products, etc.
Retrieve information online through hyperlinks, with the click of a button.
Include spreadsheets, video clips, sound clips and other applications directly in documents.

With HTML, authors describe the structure of pages using markup. The language’s elements label parts of the content as “paragraph”, “list”, “table”, etc.

What is XHTML?

XHTML is a variant of HTML that uses the syntax of XML, the extensible markup language. It has the same elements as HTML (for paragraphs, etc.), but with a slightly different syntax. Being an XML application, it can use other XML tools, such as XSLT, a language for transforming XML content.

What is CSS?

CSS is the language for describing the presentation of web pages: colors, layout, and fonts. It allows the presentation to be adapted to different types of devices, such as large screens, small screens, or printers. CSS is independent of HTML and can be used with any XML-based markup language. Separating HTML from CSS makes it easier to maintain sites, share style sheets across pages, and adapt them to different environments — what's known as *separation of structure and presentation*.

What are WebFonts?

WebFonts are a technology that lets you use fonts on demand across the web, without needing to install them on the operating system. Until recently, downloadable fonts weren’t common on the web due to the lack of an interoperable format — the WebFonts effort created an open font format for the web (WOFF), supported across the whole industry.