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A web page can be static or dynamic. Static pages are hypertexts in HTML format, and dynamic pages use scripting languages.
Each web page has one or more URLs (Universal Resource Locator), which is a permanent link to be able to reach the page. The URL is the address that users type in their browser to display a page.
HTML (Hyper Text Mark-Up Language) was developed in the 1980s by Tim Berners-Lee at CERN in Geneva, and it was used by researchers to use and share documents.
HTML is a public domain language, and the syntax is established by the World Wide Web Consortium (W3C): over the years it has been considerably revised, and the latest version is the 4.01, released in 1999. Following a period of inactivity, when the W3C concentrated mainly on the definitions of XHTML (HTML application of rules and syntax in XML style) and stylesheets (Cascading Style Sheet, CSS), work started again in 2007 to define HTML5, which has been published as a W3C Recommendation since October 2014.
As HTML is a mark-up language, and not a programming language, there are no means of interacting with it: it does, however employ markers, that are called "tags", which indicate how the various elements in a page are to be displayed.
HTML pages all have an identical structure:
The DTD passes the URL of the HTML specifications being used for the document to the browser, so that this knows which elements, attributes and entities can be legitimately used.
This section contains the actual contents of the document.
HTML has tags for many different formatting requirements and for many features. It is as well to remember, though, that it was conceived to define the logical content and not the final aspect of a document. Although it has long been used for the latter purpose, it still remains a language that should be used only to define a document's structure. Stylesheets should be used to define a document's aspect.
HTML5 is an evolution of HTML 4.01 and introduces many new features, mainly aimed at separating a page's structure (defined by the tags) from its aspect (defined by CSSs) and the actual contents. It introduces functions that, up until now, were implemented with non-standard methods, and it guarantees cross-browser compatibility, and web-based applications can be used even in the absence of the Internet. Widely used, HTML5 was published as a W3C Recommendation in October 2014.
Cascading Style Sheets (CSS) is a stylesheet language for describing how a document, written in a markup language (e.g. HTML and XHTML), is to look like (for example, fonts, spacing and colors). It was introduced due to the need to separate the contents from the formatting, so offering a clearer and easier programming, both for HTML page authors and the users.
The rules for creating stylesheets are maintained in Recommendations that W3C has been publishing since 1996. The CSS 2 specifications are the natural evolution of CSS 1. They were first published in 1998, and CSS 2.1 in 2004. The CSS 3 specifications consist of various "modules" which are currently at differing stages of completion and stability.
WebSite X5 automatically generates HTML5 code and uses CSS 2.1 or CSS 3 stylesheets, according to browser support, to define how contents are to be displayed. The advantages of using this code are:
Pages are created so that they can be used even when the user has deactivated the CSSs during navigation. In this case, the pages are linearized, which means they lose some formatting and graphics but the contents are presented in sequential order and maintain internal links (skip links not otherwise visible), which makes navigation easier.
Browsers provide the necessary commands to check whether CSSs have been disabled.