当前位置: 首页 > 图文教程 > 网页制作 > CSS样式表 > 英文教程:五种CSS选择器类型

CSS样式表
CSS+DIV 拼图(26个英文字母)
css 模拟表格斜线
hr 样式实现1px直线
css 画的百度LOGO
css 文字上右下环绕广告的写法
CSS 实现未知内容高度的垂直水平居中(改良版)
input 按钮显示差异的解决方法
css 限定GridView宽度并加上滚动条
ie6 position-fixed效果
css 书写技巧 CSS 技巧教程
IE和FireFox JavaScript的函数名的作用域的异同
纯CSS 级联菜单实现代码
CSS 清除网页浮动 经验
id与class的使用原则 网页制作经验
CSS expression判断表达式设置input样式
应用IE6所不支持的CSS的type选择器
CSS 网页内容换行控制
DIV+CSS 网页布局心得
CSS 教程之内容设置的一些语法
用div和ul标签画表格进行布局兼容火狐、ie6、ie7、Opera等浏览器

No. « 18 19 20 21 »

技术文章搜索

关键字

CSS样式表 中的 英文教程:五种CSS选择器类型

出处:互联网   整理: 软晨网（RuanChen.com）   发布: 2009-09-11   浏览: 161 ::
收藏到网摘: n/a


                         英文教程:五种CSS选择器类型.              CSScommandsareusuallygroupedinthecurlybracestomakeasetofrules.FollowingarethevariouswaysavailabletoattachthesesetofruleswithHTMLcode.
Selector(insimplewords)meanshowyounamethesesetofrules.
1CLASSSelectORS
ClassselectorsisthesimplestformofselectorswhereyouassignyourownmeaningfulnametothesetofCSSrules.Tocreateaclassselectoryousimplyneedtowritenameoftheclassfollowedbyaperiod.
(Aclassnamecannotstartwithanumberorasymbolasitisnotsupportedbyvariousbrowsers.)
Forexample,
p.big{font-weight:bold;font-size:12px;}
.center{text-align:center;}
AndthisHTML:
<pclass="big">Thisparagraphwillberenderedbold.www.ruanchen.com</p>
Youcanapplymorethanoneclasstoagivenelement.
AndthisHTML:
<pclass="centerbig">Thisparagraphwillberenderedbold.</p>
Intheaboveexample.bigand.centerarenameofCSSclassesandtheseclassesareappliedtoPtaginHTML.
IfclassnameisfollowedbyHTMLelementinyourCSScodelikep.biginaboveexampleitmeansthatthisclasswillworkonPtagonly.
OtherwiseyoucanapplytheCSSclassonanyelement.
It’sagoodpracticetoaddHTMLelementbeforeclassnameinCSSifyouarewritingCSSrulesforaparticularelement(ItaddsmoreclaritytoCSScode.
2IDSelectORS
IDselectorsworklikeclassselectors,exceptthattheycanonlybeusedononeelementperpagebecausetheyworkwithIDofthehtmlelement.TheidselectorisdefinedasidoftheHTMLelementfollowedbya#symbol.
Forexample,
p#navigation{width:12em;color:#666;font-weight:bold;}
AndthisHTML:
<pid="navigation">Thisparagraphwillberenderedbold.www.ruanchen.com</p>
AsagoodpracticeIDselectorsmustbeusedifyouarewritingtheCSScodeforasingleHTMLelementonly.IDselectorsarewellsupportedacrossstandards-compliantbrowsers.
3TAGSelectOR
TagselectorisanothersimplemethodofCSSrulesimplementation.YoucanusethisselectortoredefinetherulesforaparticularHTMLelement.
Forexample:
p{color:#999;font-weight:bold;}
IntheaboveexampleCSScodewillbeautomaticallyappliedoneveryptag.
4DESCENDENTSelectORS
Descendentselectorsspecifythatstylesshouldonlybeappliedwhentheelementinquestionisadescendent(forexample,achild,oragrandchild)ofanotherelement.
Forexample,
h3em{color:white;background-color:black;}
AndthisHTML:
<h3>Thisis<em>emphasized</em>www.ruanchen.com</h3>
Intheaboveexampleemisdescendentofh3element.Abovecssrulewillautomaticallybeappliedonallemelementsinsideh3elementintheHTMLcode.Descendentselectorsarewellsupportedacrossstandards-compliantbrowsers.
5GROUPINGSelectORS
Youcanalsospecifythesamesetofrulesformorethanoneselctor,likethis:
p,h1,h2{text-align:left;}
Justplaceacommabetweeneachone.
Youcanevengetmorecomplex,andgroupmultipleclassandidselectors:
p.navigation,h1#title{font-weight:bold;}