CSS选择器之属性选择器
1:[attr] 存在此属性即可 2:[attr = 'attr_value'] 属性值为给定值即可 3:[attr ^= 'attr_value'] attr属性键以container开头 即便是字符串匹配<style type="text/css"> div[data-type ^= 'container'] { background-color : #000; }</style><div data-type="container master"> 开头存在 container 匹配成功</div><div data-type="containernosensestr"> 开头存在 container 匹配成功</div><div data-type="master container"> 不在开头 匹配失败</div>4:[attr *= 'attr_value'] attr属性键中存在给定的值即可 即便是字符串匹配
<style type="text/css"> div[data-type *= 'container'] { background-color : #00f; }</style><div data-type="nosensestrcontainernosensestr"> 只要键值中有给定的值即可匹配成功</div>5:[attr $= 'attr_value'] attr属性键结尾匹配 即便是字符串匹配
<style type="text/css"> div[data-type $= 'container'] { background-color : #0ff; }</style><div data-type="container master"> 结尾不存在 失败</div><div data-type="nosensestrcontainer"> 结尾存在 成功</div><div data-type="master container"> 结尾存在 成功</div>6:[attr ~= 'attr_value'] attr属性键值以空格分隔 其中存在给定的值即可匹配成功
<style type="text/css"> div[data-type ~= 'container'] { background-color : #f00; }</style><div data-type="container master"> 空格拆分 存在container 匹配成功</div><div data-type="containernosensestr"> 不存在 失败</div><div data-type="master container"> 空格拆分 存在container 匹配成功</div>7:[attr |= 'attr_value'] attr属性键值以 "-" 分隔 且拆分得到的第一个值为给给定属性值 匹配成功
<style type="text/css"> div[data-type |= 'container'] { background-color : #f0f; }</style><div data-type="container-master"> -拆分 第一个值为container 匹配成功</div><div data-type="containernosensestr"> 不存在 失败</div><div data-type="master-container"> -拆分 第一个值不是container 匹配失败</div>
CSS选择器之优先级
ID选择器 100 类选择器 10 元素选择器 1
大家都知道 内联 > 内部 > 外部 而且样式内外样式表会因定义或引入的先后顺序后者覆盖前者
但样式选择器的优先级并不会因定义的先后顺序而发生覆盖
#container .article p { background-color:#000; font-size:14px;/* 无效 后面的 important 会优先于一切选择器的定义*/}//并不能覆盖前者 优先级低于前者.article p { background-color:#fff; font-size:14px;/* 无效 后面的 important 会优先于一切选择器的定义*/}//同上p { background-color:#ccc; font-size:16px!important;/*important 会优先于一切选择器的定义*/}
但以上都会被指定为 important 属性覆盖掉

The future trends of HTML are semantics and web components, the future trends of CSS are CSS-in-JS and CSSHoudini, and the future trends of JavaScript are WebAssembly and Serverless. 1. HTML semantics improve accessibility and SEO effects, and Web components improve development efficiency, but attention should be paid to browser compatibility. 2. CSS-in-JS enhances style management flexibility but may increase file size. CSSHoudini allows direct operation of CSS rendering. 3.WebAssembly optimizes browser application performance but has a steep learning curve, and Serverless simplifies development but requires optimization of cold start problems.

The roles of HTML, CSS and JavaScript in web development are: 1. HTML defines the web page structure, 2. CSS controls the web page style, and 3. JavaScript adds dynamic behavior. Together, they build the framework, aesthetics and interactivity of modern websites.

The future of HTML is full of infinite possibilities. 1) New features and standards will include more semantic tags and the popularity of WebComponents. 2) The web design trend will continue to develop towards responsive and accessible design. 3) Performance optimization will improve the user experience through responsive image loading and lazy loading technologies.

The roles of HTML, CSS and JavaScript in web development are: HTML is responsible for content structure, CSS is responsible for style, and JavaScript is responsible for dynamic behavior. 1. HTML defines the web page structure and content through tags to ensure semantics. 2. CSS controls the web page style through selectors and attributes to make it beautiful and easy to read. 3. JavaScript controls web page behavior through scripts to achieve dynamic and interactive functions.

HTMLisnotaprogramminglanguage;itisamarkuplanguage.1)HTMLstructuresandformatswebcontentusingtags.2)ItworkswithCSSforstylingandJavaScriptforinteractivity,enhancingwebdevelopment.

HTML is the cornerstone of building web page structure. 1. HTML defines the content structure and semantics, and uses, etc. tags. 2. Provide semantic markers, such as, etc., to improve SEO effect. 3. To realize user interaction through tags, pay attention to form verification. 4. Use advanced elements such as, combined with JavaScript to achieve dynamic effects. 5. Common errors include unclosed labels and unquoted attribute values, and verification tools are required. 6. Optimization strategies include reducing HTTP requests, compressing HTML, using semantic tags, etc.

HTML is a language used to build web pages, defining web page structure and content through tags and attributes. 1) HTML organizes document structure through tags, such as,. 2) The browser parses HTML to build the DOM and renders the web page. 3) New features of HTML5, such as, enhance multimedia functions. 4) Common errors include unclosed labels and unquoted attribute values. 5) Optimization suggestions include using semantic tags and reducing file size.

WebdevelopmentreliesonHTML,CSS,andJavaScript:1)HTMLstructurescontent,2)CSSstylesit,and3)JavaScriptaddsinteractivity,formingthebasisofmodernwebexperiences.


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