CSS practical tutorial 1

CSS (Cascading Stylesheets) is a new technology used to create web pages. It is now supported by most browsers and has become an indispensable tool for web page design. CSS can simplify the format code of the webpage, accelerate the download and display speed, reduce the number of code to be uploaded, and greatly reduce the workload of repetitive work. Especially when you are dealing with hundreds of web pages, CSS is a gift from God! Pai_^
Preface
CSS (Cascading Stylesheets) is a new technology used to create web pages. It is now supported by most browsers and has become an indispensable tool for web page design.
W3C (The World Wide Web Consortium) divides Dynamic HTML (Dynamic HTML) into three parts for implementation: script language (including javas runtime, Vbs runtime, etc) browsers that support dynamic effects (including Internet Explorer and Netscape Navigator) and CSS style sheets.
I. Features of stacked style sheets
Not to mention the lack of dynamic web pages in the past, that is, there are also many difficulties in the layout of webpage content. If it is not a professional or especially patient person, it is difficult for a webpage to display information based on its own ideas and ideas. Even those who have mastered the essence of the HTML language can control the formatting of such information through multiple tests. The process is very long and painful. For the development of the Internet, more people can step into this colorful world as soon as possible, and the new HTML auxiliary tools are coming soon.
A style sheet is born under such a demand. The first thing it needs to do is to precisely locate the elements on the webpage, so that the webpage designer can be like a director, it is easy to control actors composed of texts and images and perform well on the webpage as required by the script.
Secondly, it separates the content structure and format control on the webpage. The viewer wants to view the content structure on the webpage. In order to make the viewer better see the information, it is necessary to use format control to help. In the past, the distribution of the two on the web page was staggered and it was inconvenient to view and modify. Now, separating the two will greatly facilitate the web page designers. The content structure and format control are separated so that the webpage can be composed of content, and the format control of all webpages points to a CSS style sheet file. In this way, the performance is shown in two aspects:
First, the format code of the webpage is simplified, and the external style sheet will be saved in the cache by the browser, accelerating the download and display speed, it also reduces the number of codes to be uploaded (because the format set repeatedly will be saved only once ).
Second, you only need to modify and save the CSS style sheet file in the website format to change the style and features of the entire site. This is especially useful when you modify a large number of websites. The modification of one web page is avoided, greatly reducing the workload of repetitive work. When you are faced with hundreds of web pages, CSS is like a gift from God! Pai_^