Getting started with CSS learning for beginners_html/css_WEB-ITnose

1. Basic learning

1. What is CSS

CSS is the abbreviation of Cascading Style Sheets. It is a markup language. It does not require compilation and can be directly used by the browser. Execution (belongs to browser interpreted language).

The CSS file can also be said to be a text file. It contains some CSS tags. The CSS file must use css as the file name suffix. You can simply change the CSS file , changing the overall presentation of a web page can reduce our workload, so it is a required course for every web designer.

2. Syntax

2.1 Quotation

Link type (href

	<link rel="stylesheet" type="text/css" href="http://www.dreamdu.com/style.css">

href -- specify the need The address URI of the loaded resource (CSS file)
                                                                                                                                     . >
Import style (@import

>

	<style type="text/css">@import url(http://www.dreamdu.com/style.css);</style>	

Note: The style tag should be inside the head tag.

Inline styles

<style type="text/css">/* ----------文字样式开始---------- *//* 梦之都白色12象素文字 */.dreamduwhite12px { 	color:white; 	font-size:12px; }/* 梦之都黑色16象素文字 */.dreamdublack16px { 	color:black; 	font-size:16px; }/* ----------文字样式结束---------- */</style>

Apply CSS styles directly to XHTML tags.

2.2 Choices

CSS selector is the name of a CSS style. When a CSS style is displayed in an XHTML document, a CSS is used.

<p style="font-size: 10px; color: #FFFFFF;">	使用CSS内联引用表现段落.</p>

                                                                                                                  🎜>

                                                                         >

ID Selector

                                                                                         table > Summary of the usage of id and class selectors in CSS and XHTML

Writing in CSS

XHTML

Tag selector

p{ font-size:12px;}

www.dreamdu.com

id selector

#id_selector{font-size:12px;}

id与class选择符在CSS与XHTML中的用法总结
	CSS中的写法	XHTML中的写法
标签选择符	p{font-size:12px;}	www.dreamdu.com
id选择符	#id_selector{font-size:12px;}	梦之都
class选择符	.class_selector{font-size:12px;}	梦之都

Dream City class selector td> .class_selector{font-size:12px;}

Dream City

3. Advantages

Separation of content and performance. With CSS, the content (XHMTL) and performance of the web page can be separated.

Using CSS can reduce the amount of code on the web page and increase the browsing speed of the web page

2. Summary

1. Map

2. Analysis of difficulties

2.1 The difference between link style (link) and import style (@import) in external reference CSS

(1) They belong to different categories.

Link belongs to the XHTML tag, and @import is completely a method provided by CSS.
In addition to loading CSS, the link tag can also do many other things, such as defining RSS, defining rel connection attributes, etc. @import can only load CSS.
(2) Difference in loading order.

When a page is loaded (that is, when viewed by a viewer), the CSS referenced by link will be loaded at the same time, while the CSS referenced by @import will wait until the page is completely downloaded before being loaded. So sometimes when browsing the page where @import loads CSS, there will be no style at first (it just flickers), which is quite obvious when the network speed is slow.
            (3) Differences in compatibility.

Since @import was proposed by CSS2.1, old browsers do not support it. @import can only be recognized by IE5 or above, but the link tag does not have this problem.
(4) Differences in using DOM to control styles.

When using JavaScript to control the dom to change the style, you can only use the link tag, because @import cannot be controlled by the dom.

2.2 The difference between tables and forms

Tables are used for layout, and forms are used to transmit data. Forms can be included in tables, and tables can also be included in forms. Use tables to Lay out the data in the form,

If you have data to provide to the background program, such as an input box, text box, etc., these elements usually need to be placed in a form so that the data submission can be completed.

3. Editor’s message

CSS is mainly used to control the style of web page display. Through CSS, the content in HTML can show brilliant effects, just like applying makeup to a person. If used appropriately, the effect will be good.

This article only organizes some simple content of CSS. As for other powerful functions, we still need to continue to explore and gradually deepen in future studies.

Related reading: Basic basic CSS tutorial