css selector 用法

Selector	Example	Example description.class	.intro	Selects all elements with class="intro".class1.class2	.name1.name2	Selects all elements with both name1 and name2 set within its class attribute.class1 .class2	.name1 .name2	Selects all elements with name2 that is a descendant of an element with name1#id	#firstname	Selects the element with id="firstname"*	*	Selects all elementselement	p	Selects all <p> elementselement.class	p.intro	Selects all <p> elements with class="intro"element,element	div, p	Selects all <div> elements and all <p> elementselement element	div p	Selects all <p> elements inside <div> elementselement>element	div > p	Selects all <p> elements where the parent is a <div> elementelement+element	div + p	Selects the first <p> element that is placed immediately after <div> elementselement1~element2	p ~ ul	Selects every <ul> element that is preceded by a <p> element[attribute]	[target]	Selects all elements with a target attribute[attribute=value]	[target=_blank]	Selects all elements with target="_blank"[attribute~=value]	[title~=flower]	Selects all elements with a title attribute containing the word "flower"[attribute|=value]	[lang|=en]	Selects all elements with a lang attribute value equal to "en" or starting with "en-"[attribute^=value]	a[href^="https"]	Selects every <a> element whose href attribute value begins with "https"[attribute$=value]	a[href$=".pdf"]	Selects every <a> element whose href attribute value ends with ".pdf"[attribute*=value]	a[href*="w3schools"]	Selects every <a> element whose href attribute value contains the substring "w3schools":active	a:active	Selects the active link::after	p::after	Insert something after the content of each <p> element::before	p::before	Insert something before the content of each <p> element:checked	input:checked	Selects every checked <input> element:default	input:default	Selects the default <input> element:disabled	input:disabled	Selects every disabled <input> element:empty	p:empty	Selects every <p> element that has no children (including text nodes):enabled	input:enabled	Selects every enabled <input> element:first-child	p:first-child	Selects every <p> element that is the first child of its parent::first-letter	p::first-letter	Selects the first letter of every <p> element::first-line	p::first-line	Selects the first line of every <p> element:first-of-type	p:first-of-type	Selects every <p> element that is the first <p> element of its parent:focus	input:focus	Selects the input element which has focus:fullscreen	:fullscreen	Selects the element that is in full-screen mode:hover	a:hover	Selects links on mouse over:in-range	input:in-range	Selects input elements with a value within a specified range:indeterminate	input:indeterminate	Selects input elements that are in an indeterminate state:invalid	input:invalid	Selects all input elements with an invalid value:lang(language)	p:lang(it)	Selects every <p> element with a lang attribute equal to "it" (Italian):last-child	p:last-child	Selects every <p> element that is the last child of its parent:last-of-type	p:last-of-type	Selects every <p> element that is the last <p> element of its parent:link	a:link	Selects all unvisited links::marker	::marker	Selects the markers of list items:not(selector)	:not(p)	Selects every element that is not a <p> element:nth-child(n)	p:nth-child(2)	Selects every <p> element that is the second child of its parent:nth-last-child(n)	p:nth-last-child(2)	Selects every <p> element that is the second child of its parent, counting from the last child:nth-last-of-type(n)	p:nth-last-of-type(2)	Selects every <p> element that is the second <p> element of its parent, counting from the last child:nth-of-type(n)	p:nth-of-type(2)	Selects every <p> element that is the second <p> element of its parent:only-of-type	p:only-of-type	Selects every <p> element that is the only <p> element of its parent:only-child	p:only-child	Selects every <p> element that is the only child of its parent:optional	input:optional	Selects input elements with no "required" attribute:out-of-range	input:out-of-range	Selects input elements with a value outside a specified range::placeholder	input::placeholder	Selects input elements with the "placeholder" attribute specified:read-only	input:read-only	Selects input elements with the "readonly" attribute specified:read-write	input:read-write	Selects input elements with the "readonly" attribute NOT specified:required	input:required	Selects input elements with the "required" attribute specified:root	:root	Selects the document's root element::selection	::selection	Selects the portion of an element that is selected by a user:target	#news:target	Selects the current active #news element (clicked on a URL containing that anchor name):valid	input:valid	Selects all input elements with a valid value:visited	a:visited	Selects all visited links