What are the three main forms of using css on the page?-Front-end Q&A-php.cn

What are the three main forms of using css on the page?

青灯夜游

Release： 2023-01-07 11:41:37

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Three forms: 1. Write the style in the style attribute of the tag, the syntax is ""; 2. Write the style in the style tag pair, the syntax is "< ;style>code”; 3. Put the css code into the “.css” file and introduce it using the link tag.

What are the three main forms of using css on the page?

The operating environment of this tutorial: Windows7 system, CSS3&&HTML5 version, Dell G3 computer.

1. Inline style

sets the style of the element through the style attribute of the tag. Its basic syntax format is as follows:

<element style="属性:值;属性:值;...">内容</element>

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style in syntax It is an attribute of the tag. In fact, any HTML tag has the style attribute, which is used to set the inline style. The writing specification of the attribute value is the same as the CSS style rule. The inline style works on all its tags and the subtags nested in it. .

2. Internal style sheet

Embedded style is to write the css code in the head tag of the HTML document and define it with the style tag. Its basic The syntax format is as follows:

<head>  
<style type="text/css"> 
css选择器{ 
  属性:值;
  属性:值;
}
</style> 
</head>

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In syntax, the style tag is generally located after the head tag, and it can also be placed anywhere in the HTML document.

3. External link style

The linked style is to place all styles in one or more external style sheet files with CSS as the extension. The link tag links external styles to the HTML document. Its basic syntax format is as follows:

<link rel="stylesheet" type="text/css" href="css文件路径" />

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Attribute	Description
rel	Define the relationship between the current document and other linked documents. "stylesheet" means: the linked document is a style sheet file
href	Define the URL of the linked external style sheet file, which can be a relative path or an absolute path

Advantages:

Complete separation of structure and performance code
Facilitates reuse and maintenance
Because Separating into separate files greatly reduces the size of HTML files, making the page structure easier to read by programmers and web crawlers
Friendly to search engines, making search engines Give the page a higher score, which is beneficial to the page's search engine ranking
The external style sheet is cached on the user's computer after the user's first visit, and does not need to be loaded on the next visit

Disadvantages:

If there are many styles, the CSS file will become very large and difficult to find. In addition, one more CSS file means one more HTTP request, which will increase the pressure on the server on a website with a large number of visits

(Learning video sharing: css video tutorial)

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