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

HTMLtagsdefinethestructureofawebpage,whileattributesaddfunctionalityanddetails.1)Tagslike,,andoutlinethecontent'splacement.2)Attributessuchassrc,class,andstyleenhancetagsbyspecifyingimagesources,styling,andmore,improvingfunctionalityandappearance.

The future of HTML will develop in a more semantic, functional and modular direction. 1) Semanticization will make the tag describe the content more clearly, improving SEO and barrier-free access. 2) Functionalization will introduce new elements and attributes to meet user needs. 3) Modularity will support component development and improve code reusability.

HTMLattributesarecrucialinwebdevelopmentforcontrollingbehavior,appearance,andfunctionality.Theyenhanceinteractivity,accessibility,andSEO.Forexample,thesrcattributeintagsimpactsSEO,whileonclickintagsaddsinteractivity.Touseattributeseffectively:1)Usese

The alt attribute is an important part of the tag in HTML and is used to provide alternative text for images. 1. When the image cannot be loaded, the text in the alt attribute will be displayed to improve the user experience. 2. Screen readers use the alt attribute to help visually impaired users understand the content of the picture. 3. Search engines index text in the alt attribute to improve the SEO ranking of web pages.

The roles of HTML, CSS and JavaScript in web development are: 1. HTML is used to build web page structure; 2. CSS is used to beautify the appearance of web pages; 3. JavaScript is used to achieve dynamic interaction. Through tags, styles and scripts, these three together build the core functions of modern web pages.

Setting the lang attributes of a tag is a key step in optimizing web accessibility and SEO. 1) Set the lang attribute in the tag, such as. 2) In multilingual content, set lang attributes for different language parts, such as. 3) Use language codes that comply with ISO639-1 standards, such as "en", "fr", "zh", etc. Correctly setting the lang attribute can improve the accessibility of web pages and search engine rankings.

HTMLattributesareessentialforenhancingwebelements'functionalityandappearance.Theyaddinformationtodefinebehavior,appearance,andinteraction,makingwebsitesinteractive,responsive,andvisuallyappealing.Attributeslikesrc,href,class,type,anddisabledtransform

TocreatealistinHTML,useforunorderedlistsandfororderedlists:1)Forunorderedlists,wrapitemsinanduseforeachitem,renderingasabulletedlist.2)Fororderedlists,useandfornumberedlists,customizablewiththetypeattributefordifferentnumberingstyles.


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