css reset_浏览器样式重置

css reset出现原因

因不同浏览器对css的解析效果存在差异，为了减少各种浏览器下默认样式的差异，采用此方法重置元素在不同浏览器下的默认值。

最开始的reset css 方式

* {
    padding: 0;
    margin: 0;
}

此方法的学名为：Global White Space Reset，最开始css reset的方式，但是这种方式存在一定的弊端：

1. * 导致css渲染引擎在渲染css的时候，使用 * 遍历整个DOM树，影响渲染性能
2. * 由于是对所有标签元素的重置样式，因此对于不必须的样式重置也会被重置。

reset.css

html, body, div, span, applet, object, iframe,
h1, h2, h3, h4, h5, h6, p, blockquote, pre,
a, abbr, acronym, address, big, cite, code,
del, dfn, em, img, ins, kbd, q, s, samp,
small, strike, strong, sub, sup, tt, var,
b, u, i, center,
dl, dt, dd, ol, ul, li,
fieldset, form, label, legend,
table, caption, tbody, tfoot, thead, tr, th, td,
article, aside, canvas, details, embed, 
figure, figcaption, footer, header, hgroup, 
menu, nav, output, ruby, section, summary,
time, mark, audio, video {
	margin: 0;
	padding: 0;
	border: 0;
	font-size: 100%;
	font: inherit;
	vertical-align: baseline;
}
/* HTML5 display-role reset for older browsers */
article, aside, details, figcaption, figure, 
footer, header, hgroup, menu, nav, section {
	display: block;
}
body {
	line-height: 1;
}
ol, ul {
	list-style: none;
}
blockquote, q {
	quotes: none;
}
blockquote:before, blockquote:after,
q:before, q:after {
	content: '';
	content: none;
}
table {
	border-collapse: collapse;
	border-spacing: 0;
}

最初作者：Eric Meyer
目的：在各个浏览器达到统一性
reset.css原文.

Normalize.css

由 Nicolas Gallagher 和 Jonathan Neal 维护的一个CSS 重置样式库，Bootstrap用的就是normalize.css。

/*! normalize.css v3.0.1 | MIT License | git.io/normalize */
html {
    font-family: sans-serif;
    -ms-text-size-adjust: 100%;
    -webkit-text-size-adjust: 100%
}

body {
    margin: 0
}

article, aside, details, figcaption, figure, footer, header, hgroup, main, nav, section, summary {
    display: block
}

audio, canvas, progress, video {
    display: inline-block;
    vertical-align: baseline
}

audio:not([controls]) {
    display: none;
    height: 0
}

[hidden], template {
    display: none
}

a {
    background: transparent
}

a:active, a:hover {
    outline: 0
}

abbr[title] {
    border-bottom: 1px dotted
}

b, strong {
    font-weight: bold
}

dfn {
    font-style: italic
}

h1 {
    font-size: 2em;
    margin: .67em 0
}

mark {
    background: #ff0;
    color: #000
}

small {
    font-size: 80%
}

sub, sup {
    font-size: 75%;
    line-height: 0;
    position: relative;
    vertical-align: baseline
}

sup {
    top: -0.5em
}

sub {
    bottom: -0.25em
}

img {
    border: 0
}

svg:not(:root) {
    overflow: hidden
}

figure {
    margin: 1em 40px
}

hr {
    -moz-box-sizing: content-box;
    box-sizing: content-box;
    height: 0
}

pre {
    overflow: auto
}

code, kbd, pre, samp {
    font-family: monospace, monospace;
    font-size: 1em
}

button, input, optgroup, select, textarea {
    color: inherit;
    font: inherit;
    margin: 0
}

button {
    overflow: visible
}

button, select {
    text-transform: none
}

button, html input[type="button"], input[type="reset"], input[type="submit"] {
    -webkit-appearance: button;
    cursor: pointer
}

button[disabled], html input[disabled] {
    cursor: default
}

button::-moz-focus-inner, input::-moz-focus-inner {
    border: 0;
    padding: 0
}

input {
    line-height: normal
}

input[type="checkbox"], input[type="radio"] {
    box-sizing: border-box;
    padding: 0
}

input[type="number"]::-webkit-inner-spin-button, input[type="number"]::-webkit-outer-spin-button {
    height: auto
}

input[type="search"] {
    -webkit-appearance: textfield;
    -moz-box-sizing: content-box;
    -webkit-box-sizing: content-box;
    box-sizing: content-box
}

input[type="search"]::-webkit-search-cancel-button, input[type="search"]::-webkit-search-decoration {
    -webkit-appearance: none
}

fieldset {
    border: 1px solid #c0c0c0;
    margin: 0 2px;
    padding: .35em .625em .75em
}

legend {
    border: 0;
    padding: 0
}

textarea {
    overflow: auto
}

optgroup {
    font-weight: bold
}

table {
    border-collapse: collapse;
    border-spacing: 0
}

td, th {
    padding: 0
}

normalize.css源码链接.

淘宝

body, h1, h2, h3, h4, h5, h6, hr, p, blockquote, dl, dt, dd, ul, ol, li, pre,
form, fieldset, legend, button, input, textarea, th, td {
    margin: 0;
    padding: 0;
}

body, button, input, select, textarea {
    font: 12px/1.5 tahoma, arial, \5b8b\4f53;
}

h1, h2, h3, h4, h5, h6 {
    font-size: 100%;
}

address, cite, dfn, em, var {
    font-style: normal;
}

code, kbd, pre, samp {
    font-family: courier new, courier, monospace;
}

small {
    font-size: 12px;
}

ul, ol {
    list-style: none;
}

a {
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

sup {
    vertical-align: text-top;
}

sub {
    vertical-align: text-bottom;
}

legend {
    color: #000;
}

fieldset, img {
    border: 0;
}

button, input, select, textarea {
    font-size: 100%;
}

table {
    border-collapse: collapse;
    border-spacing: 0;
}

搜狐

/* 全局CSS定义 */
body {
    font-family: '宋体';
    text-align: center;
    margin: 0 auto;
    padding: 0;
    background: #FFF;
    font-size: 12px;
    color: #333;
}

body > div {
    text-align: center;
    margin-right: auto;
    margin-left: auto;
}

div, form, ul, ol, li, span, p {
    margin: 0;
    padding: 0;
    border: 0;
}

img, a img {
    border: 0;
    margin: 0;
    padding: 0;
}

h1, h2, h3, h4, h5, h6 {
    margin: 0;
    padding: 0;
    font-size: 12px;
    font-weight: normal;
}

ul, ol, li {
    list-style: none
}

table, td, input {
    font-size: 12px;
    padding: 0
}

/* 默认链接颜色 */
a {
    outline-style: none;
    color: #333;
    text-decoration: none
}

a:hover {
    color: #c00;
    text-decoration: underline;
}

总结

不同项目css reset适用性不一致，应该按需求来进行使用。

参考文章：1. https://www.zhangxinxu.com/wordpress/2010/07/%E6%88%91%E6%98%AF%E5%A6%82%E4%BD%95%E5%AF%B9%E7%BD%91%E7%AB%99css%E8%BF%9B%E8%A1%8C%E6%9E%B6%E6%9E%84%E7%9A%84/
2. https://blog.csdn.net/phphot/article/details/4354979