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Lecture Web technology and online services: Lesson 3 - CSS

Lecture "Web Technology and online services: Lesson 3 - CSS" provide students with knowledge about: Overview of basic CSS; Overview of advanced CSS; . Please refer to the detailed content of the lecture! | CSS 1 Content Basic CSS Advanced CSS Basic CSS 3 Content vs. Presentation Most HTML tags define content type independent of presentation. exceptions e.g. for bold text and . for italicized text Style sheets associate presentation formats with HTML elements. CSS1 developed in 1996 by W3C CSS2 released in 1998 but still not fully supported by all browsers CSS3 specification still under development by the W3C completely backwards compatible with CSS2 according to the W3C The trend has been towards an increasing separation of the content of webpages from the presentation of them. Style sheets allow us to maintain this separation which allows for easier maintenance of webpages and for a consistent look across a collection of webpages. Content vs. Presentation cont. Style sheets can be used to specify how tables should be rendered how lists should be presented what colors should be used on the webpage what fonts should be used and how big small they are etc. HTML style sheets are known as Cascading Style Sheets since can be defined at three different levels 1. inline style sheets apply to the content of a single HTML element 2. document style sheets apply to the whole BODY of a document 3. external style sheets can be linked and applied to numerous documents might also specify how things should be presented on screen or in print lower-level style sheets can override higher-level style sheets User-defined style sheets can also be used to override the specifications of the webpage designer. These might be used say to make text larger e.g. for visually-impaired users . 5 Inline Style Sheets Using the style attribute you can specify presentation style for a single HTML element within tag list sequence of property value pairs Inline Style Sheets separated by semi-colons font-family Courier monospace This is a font-weight bold right-justified paragraph in a sans serif font-size 12pt font-size large font-size larger font preferably Arial with some green color red color 000080