css教程:CSS基本介绍!_CSS教程

编辑Tag赚U币
教程Tag:暂无Tag,欢迎添加,赚取U币!
What You Should Already Know
Before you continue you should have some basic understanding of the following:
在继续前你应该具备相关的基础知识:HTML / XHTML

What is CSS? 什么是CSS?
CSS stands for Cascading Style Sheets
Styles define how to display HTML elements
Styles are normally stored in Style Sheets
Styles were added to HTML 4.0 to solve a problem
External Style Sheets can save you a lot of work
External Style Sheets are stored in CSS files
Multiple style definitions will cascade into one

CSS 意思就是 叠层样式表
样式定义了HTML元素怎样去显示
样式一般存储在样式表中
样式添加到HTML4.0中用来解决问题
利用外部样式表可以提高你的工作效率
外部样式表存储在CSS文件中

Styles Solve a Common Problem
用样式来解决一个共同的问题


HTML tags were originally designed to define the content of a document. They were supposed to say "This is a header", "This is a paragraph", "This is a table", by using tags like <h1>, <p>, <table>, and so on. The layout of the document was supposed to be taken care of by the browser, without using any formatting tags.
As the two major browsers - Netscape and Internet Explorer - continued to add new HTML tags and attributes (like the <font> tag and the color attribute) to the original HTML specification, it became more and more difficult to create Web sites where the content of HTML documents was clearly separated from the document's presentation layout.
To solve this problem, the World Wide Web Consortium (W3C) - the non profit, standard setting consortium, responsible for standardizing HTML - created STYLES in addition to HTML 4.0.
All major browsers support Cascading Style Sheets.

HTML标签起初被设计成为定义文档的内容。通过使用像<h1>,<p>,<table>这样的标签他们应该表达的是"这是一个标题","这是一个段落","这是一张表格",而布局该由浏览器来处理并非使用格式化标签.
作为两大浏览器 - 网景 和 IE - 不断的添加新的HTML标签和属性(像<font>标签和颜色属性)来初始HTML的规格,这让建立清楚的HTML文档内容并从形式中分离出来变的越来越困难.
为了解决这个难题,W3C 这个非赢利的,建立标准的组织,为HTML4.0增加了样式
所有主流浏览器都支持样式表

Style Sheets Can Save a Lot of Work
样式表可以提高工作效率


Styles sheets define HOW HTML elements are to be displayed, just like the font tag and the color attribute in HTML 3.2. Styles are normally saved in external .css files. External style sheets enable you to change the appearance and layout of all the pages in your Web, just by editing one single CSS document!
CSS is a breakthrough in Web design because it allows developers to control the style and layout of multiple Web pages all at once. As a Web developer you can define a style for each HTML element and apply it to as many Web pages as you want. To make a global change, simply change the style, and all elements in the Web are updated automatically.

样式表定义元素怎样去显示,就像在HTML3.2中字体标签和颜色属性一般保存在一个外部的.css文件一样.外部样式表能够让你改变所有出现在你WEB中的外观和布局,而仅仅通过编辑一个单独的CSS文档.(原理就是一动多变)
CSS是一个在设计领域中的突破,因为它答应开发者一下就能控制多个WEB页的样式和布局.作为译名WEB开发者你可以为每个HTML元素和应用他的每个页面定义一个你想要的样式.来实现全面的改变,简单的改变样式,所有与之相关的元素都会自动更新

Multiple Styles Will Cascade Into One

Style sheets allow style information to be specified in many ways. Styles can be specified inside a single HTML element, inside the <head> element of an HTML page, or in an external CSS file. Even multiple external style sheets can be referenced inside a single HTML document.
样式表答应样式信息用多种方式来定义.样式可以在一单独的HTML元素中指定,在<head>元素中或在一外部CSS文件中.甚至多个外部样表能集中在一个单一的HTML文档中

Cascading order

What style will be used when there is more than one style specified for an HTML element?
当多于一种的样式指定一HTML元素时使用怎样的样式呢?

Generally speaking we can say that all the styles will "cascade" into a new "virtual" style sheet by the following rules, where number four has the highest priority:
一般说来所有样式有下面的规则(第四个最有优先性)

Browser default
浏览器默认
External style sheet
外部样式表
Internal style sheet (inside the <head> tag)
内嵌样式表(在<head>标签内)
Inline style (inside an HTML element)
行内样式(在一HTML元素内)
So, an inline style (inside an HTML element) has the highest priority, which means that it will override a style declared inside the <head> tag, in an external style sheet, or in a browser (a default value).
所以写在HTML元素中的样式有最高的优先权(写在HTML元素内的),它会替代其他形式的样式.

来源:无忧整理//所属分类:CSS教程/更新时间:2006-11-09
相关CSS教程