CSS Authoritative Guide Reading Notes Selector_html/css_WEB-ITnose

Selector

The rule structure of the selector includes: selector and declaration block. Each declaration block is an attribute key-value pair (remember that each declaration block is best added Ending with semicolon)

        p.warning {            font-weight:bold;            /*其class属性包含词warning的所有段落*/            /*记住解释一般是从左到右读*/        }        .warning.urgent {            background:red;            /*class同时包含warning和urgent的所有元素 其中warning和urgent class没有顺序之分*/            /*选择器当中是没有空格的，如果有空格就成了子元素选择器了*/        }        img[alt] {            font-weight:bold;            /*所有带有alt属性的图像*/        }        a[href="http://www.w3.org"][title="W3C Home"] {            font-size:20px;            /*href值为http://www.w3.org和title值为W3C Home的a链接-------属性值完全匹配才行*/        }        span[class~="barren"] {            font-style:initial;            /*根据属性值中出现的一个用空格分隔的词来完成选择--部分选择值   记住是以空格分隔的一个词*/        }

Substring matching attribute selector

Specific attribute selection type

Link pseudo-class

You may know that the :link and :visited pseudo-class selectors are functionally equivalent to the link and vlink of the body attribute .

Dynamic pseudo-class

Possibly using the wrong first-child

        /*这也就是为什么从右向左翻译解释的原因*/        p:first-child {            font-weight:bold;            /*作为某元素的第一个子元素的所有p元素设置为粗体*/        }        li:first-child {            text-transform:uppercase;            /*作为某元素的第一个子元素的所有li元素变为大写*/        }

Language selector

        *:lang(fr) {            font-style:italic;        }

Pseudo element selector

        p:first-letter {            color:red;/*让段落的第一个字母变成红色*/        }        p:first-line {            color:purple;/*让段落的第一行变成紫色*/        }        h3:before {            content:"[[";            color:silver;/*在每个h3元素前加一对银色的中括号*/        }        h3:after {            content:"  The end.";/*在h3元素后固定插入...*/        }