An in-depth discussion of how CSS is defined-Front-end Q&A-php.cn

CSS (Cascading Style Sheets) is a language used to control the appearance of HTML (Hypertext Markup Language) website pages. CSS provides web designers with extensive flexibility and control. They can control the appearance and layout of elements by defining styles (Styles), thereby making web pages more beautiful and easier to read. In this article, we’ll take a deep dive into how CSS is defined.

Internal Style Sheet The Internal Style Sheet writes CSS style code directly in the tag of HTML. It is only applicable to single page. The specific method is as follows:

/* 样式代码 */ Copy after login Among them, the tag is used to define the style, and its type attribute is used to specify the type of style, usually text/css.

In the style code block, we can define multiple selectors and attributes, for example:

h1 { color: red; font-size: 24px; } p { color: blue; font-size: 16px; } Copy after login In the above code, we define two selectors: h1 and p. These two selectors represent all and elements, setting their color and font size respectively.

External Style Sheet External Style Sheet (External Style Sheet) places the CSS style code in an independent .css file and passes it through HTML's tag links it into a page, and it works on multiple pages and the entire website. The specific method is as follows:

Write the style code in an independent .css file, for example:

/* sample.css */ h1 { color: red; font-size: 24px; } p { color: blue; font-size: 16px; } Copy after login Use the tag in the tag of the HTML page to link the style file , for example:

Copy after login Among them, the rel attribute of the tag is used to specify the link type, the type attribute is used to specify the style type, and the href attribute is used to specify the link address of the style file.

Inline Style Inline Style (Inline Style) writes CSS style code directly in the style attribute of an HTML element, and it applies to a single element. The specific method is as follows:

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Copy after login Among them, the style attribute is used to specify the style of the element, and the attribute value is a style code block, similar to an internal style sheet.

Summary:

CSS style sheets can be defined in a variety of ways, including internal style sheets, external style sheets, and inline styles. Internal style sheets apply to a single page, external style sheets apply to multiple pages and the entire website, and inline styles only apply to individual elements. Different definition methods have their own advantages and disadvantages, so in practical applications, it is necessary to choose the appropriate method according to the specific situation.