Skill: Cascading style sheets (CSS)
Cascading style sheets, more commonly known as CSS, are used as a style sheet facility in HTML. They can also be used in conjunction with scripting languages such as JavaScript to change the format of an HTML document as a user interacts with the document. They form part of version 4 of HTML and enable the Web designer to define a standard visual identity for pages which have a similar function. For example, a style sheet could be used to define an entry in an online catalogue and then be applied to individual Web pages containing sales information so that they look the same. Style sheets can be defined in a separate file or can be included in an HTML file that is to be browsed. They can be constructed by hand, but this is a tedious and error-prone process. Fortunately, there are a number of special-purpose software tools available for the definition of CSS style sheets and many WYSIWYG editors provide facilities for their semi-automatic construction