CSS Reset
CSS Reset,意为重置默认样式。HTML中绝大部分标签元素在网页显示中都有一个默认属性值,通常为了避免重复定义元素样式,需要进行重置默认样式(CSS Reset)。举几个例子:
1.淘宝(CSS Reset):
html {
overflow-x:auto;
overflow-y:scroll;
}
body, dl, dt, dd, ul, ol, li, pre, form, fieldset, input, p, blockquote, th, td {
font-weight:400;
margin:0;
padding:0;
}
h1, h2, h3, h4, h4, h5 {
margin:0;
padding:0;
}
body {
background-color:#FFFFFF;
color:#666666;
font-family:Helvetica,Arial,sans-serif;
font-size:12px;
padding:0 10px;
text-align:left;
}
select {
font-size:12px;
}
table {
border-collapse:collapse;
}
fieldset, img {
border:0 none;
}
fieldset {
margin:0;
padding:0;
}
fieldset p {
margin:0;
padding:0 0 0 8px;
}
legend {
display:none;
}
address, caption, em, strong, th, i {
font-style:normal;
font-weight:400;
}
table caption {
margin-left:-1px;
}
hr {
border-bottom:1px solid #FFFFFF;
border-top:1px solid #E4E4E4;
border-width:1px 0;
clear:both;
height:2px;
margin:5px 0;
overflow:hidden;
}
ol, ul {
list-style-image:none;
list-style-position:outside;
list-style-type:none;
}
caption, th {
text-align:left;
}
q:before, q:after, blockquote:before, blockquote:after {
content:””;
}
2.百度(CSS Reset):
body {
font-family:arial,helvetica,sans-serif;
font-size:13px;
font-size-adjust:none;
font-stretch:normal;
font-style:normal;
font-variant:normal;
font-weight:normal;
line-height:1.4;
text-align:center;
}
body, ul, ol, dl, dd, h1, h2, h3, h4, h5, h6, p, form, fieldset, legend, input, textarea, select, button, th, td {
margin:0;
padding:0;
}
h1, h2, h3, h4, h5, h6 {
font-size:100%;
font-weight:normal;
}
table {
font-size:inherit;
}
input, select {
font-family:arial,helvetica,clean,sans-serif;
font-size:100%;
font-size-adjust:none;
font-stretch:normal;
font-style:normal;
font-variant:normal;
font-weight:normal;
line-height:normal;
}
button {
overflow:visible;
}
th, em, strong, b, address, cite {
font-style:normal;
font-weight:normal;
}
li {
list-style-image:none;
list-style-position:outside;
list-style-type:none;
}
img, fieldset {
border:0 none;
}
ins {
text-decoration:none;
}
3.《超越css》(CSS Reset):
/* Normalizes margin,padding */
body,div,dl,dt,dd,ul,ol,li,h1,h2,h3,h4,h5,h6,pre,form,fieldset,input,p,blockquote,th,td { margin:0;padding:0}
/* Normalizes font-size for headers */
h1,h2,h3,h4,h5,h6 { font-size:100%}
/* Removes list-style from lists */
ol,ul { list-style:none }
/* Normalizes font-size and font-weight to normal */
address,caption,cite,code,dfn,em,strong,th,var { font-size:normal; font-weight:normal }
/* Removes list-style from lists */
table { border-collapse:collapse; border-spacing:0 }
/* Removes border from fieldset and img */
fieldset,img { border:0 }
/* Left-aligns text in caption and th */
caption,th { text-align:left }
/* Removes quotation marks from q */
q:before,q:after { content:”}
4.Eric Meyer(CSS Reset)——推荐:
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, font, 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 {
margin: 0;
padding: 0;
border: 0;
outline: 0;
font-size: 100%;
vertical-align: baseline;
background: transparent;
}
body {
line-height: 1;
}
ol, ul {
list-style: none;
}
blockquote, q {
quotes: none;
}
blockquote:before, blockquote:after,
q:before, q:after {
content: ”;
content: none;
}
/* remember to define focus styles! */
:focus {
outline: 0;
}
/* remember to highlight inserts somehow! */
ins {
text-decoration: none;
}
del {
text-decoration: line-through;
}
/* tables still need ‘cellspacing=”0″‘ in the markup */
table {
border-collapse: collapse;
border-spacing: 0;
}
5.YUI(CSS Reset):
body,div,dl,dt,dd,ul,ol,li,h1,h2,h3,h4,h5,h6,pre,form,fieldset,input,textarea,p,blockquote,th,td {
margin:0;
padding:0;
}
table {
border-collapse:collapse;
border-spacing:0;
}
fieldset,img {
border:0;
}
address,caption,cite,code,dfn,em,strong,th,var {
font-style:normal;
font-weight:normal;
}
ol,ul {
list-style:none;
}
caption,th {
text-align:left;
}
h1,h2,h3,h4,h5,h6 {
font-size:100%;
font-weight:normal;
}
q:before,q:after {
content:”;
}
abbr,acronym {
border:0;
}
Normalize.css
(文章来源:https://www.jianshu.com/p/3d21d1932aa0)
Normalize.css只是一个很小的css文件,但它在默认的HTML元素样式上提供了跨浏览器的高度一致性。相比于传统的css reset,Normalize.css是一种现代的,为HTML5准备的优质替代方案。Normalize.css现在已经被用于Twitter, Bootstrap,HTML5 Boilerplate,GOV.UK,Rdio,CSS Tricks以及许许多多其他的框架,工具和网站上。
综述
Normalize.css是一种CSS reset的替代方案。经过@necolas和@jon neal花了几百个小时来努力研究不同浏览器的默认样式的差异,这个项目终于变成了现在这样。
我们创造normalize.css有下几个目的:
- 保护有用的浏览器默认样式而不是完全去掉它们
- 一般化的样式:为大部分HTML元素提供
- 修复浏览器自身的bug并保证各浏览器的一致性
- 优化CSS可用性:用一些小技巧
- 解释代码:用注释和详细的文档来
Normalize.css支持包括手机浏览器在内的许多浏览器,同时对HTML元素,排版,列表,嵌入的内容,表单和表格都进行了一般化。尽管这个项目进行了一般化的原则,但我们还是在合适的地方使用了更实用的默认值。
Normalize vs Reset
知道Normalize.css和传统的Reset的区别是非常有价值的。
1.Normalize.css保护了有价值的默认值
Reset通过为几乎所有的元素施加默认样式,强行使得元素有相同的视觉效果。相比之下,Normalize.css保持了许多默认的浏览器样式。这就意味着你不用再为所有的公共排版元素重新设置样式。当一个元素在不同的浏览器中有不同的默认值时,Normalize.css会力求让这些样式保持一致并可能与现代标准相符合。
2.Normalize.css修复了浏览器的bug
它修复了常见的桌面端和移动端浏览器的bug。这往往超出了Reset所能做到的范畴。关于这一点,Normalize.css修复的问题包含了HTML5元素的显示设置,与格式化文字的font-size问题,在IE9中SVG的溢出,许多出现在各浏览器和操作系统中的与表单相关的bug。
可以看看以下的这个例子,看看对于HTML5中新出现的input类型search,Normalize.css是如何保证跨浏览器的一致性的。
/* 1.Addresses appearance set to searchfield in ss,Chrome
* 2.Addresses box-size set to border-box in ss,Chrome(include -moz to future-proof)*/
input[type="search"]{
-webkit-appearance:textfield;
/* 1 */
-moz-box-sizing:content-box;
-webkit-box-sizing:content-box;
/* 2 */
box-sizing:content-box;
}
/*Removes inner padding and search candle button in ss,Chrome on OS X */
input[type="search"]::-webkit-search-decoration, input[type="search"]::-webkit-search-cancel-button{
-webkit-appearance:none;
}
3.Normalize.css不会让你的调试工具变得杂乱
使用Reset最让人困扰的地方莫过于在浏览器调试工具中使用大段的继承链。在Normalize.css中就不会有这样的问题,因为在我们的准则中对多选择器的使用是非常谨慎的,我们仅会有目的地对元素设置样式。
4.Normalize.css是模块化的
这个项目已经被拆分为多个相关却又独立的部分,这使得你能够很容易也很清楚地知道哪些元素被设置了特定的值。因此这能让你自己选择性地移除掉某些永远不会用到的部分(比如表单的一般化)。
5.Normalize.css拥有详细的文档
Normalize.css的代码基于详细而全面的跨浏览器研究与测试。这个文件中拥有详细的代码说明并在Github Wiki中有进一步的说明。这意味着你可以知道到每一行代码具体实现了什么工作,为什么要写这句代码,浏览器之间的差异,并且你可以更容易地实现地进行自己的测试。
这个项目的目标是帮助人们了解浏览器默认是如何渲染元素的,同时也让人们很容易地明白如何改进浏览器渲染。
如何使用Normalize.css
首先,安装或从Github下载Normalize.css,接下来有两种主要途径去使用它。(Github 地址:https://github.com/necolas/normalize.css)
源码:
/*! normalize.css v8.0.0 | MIT License | github.com/necolas/normalize.css */
/* Document
========================================================================== */
/**
* 1. Correct the line height in all browsers.
* 2. Prevent adjustments of font size after orientation changes in iOS.
*/
html {
line-height: 1.15; /* 1 */
-webkit-text-size-adjust: 100%; /* 2 */
}
/* Sections
========================================================================== */
/**
* Remove the margin in all browsers.
*/
body {
margin: 0;
}
/**
* Correct the font size and margin on `h1` elements within `section` and
* `article` contexts in Chrome, Firefox, and Safari.
*/
h1 {
font-size: 2em;
margin: 0.67em 0;
}
/* Grouping content
========================================================================== */
/**
* 1. Add the correct box sizing in Firefox.
* 2. Show the overflow in Edge and IE.
*/
hr {
box-sizing: content-box; /* 1 */
height: 0; /* 1 */
overflow: visible; /* 2 */
}
/**
* 1. Correct the inheritance and scaling of font size in all browsers.
* 2. Correct the odd `em` font sizing in all browsers.
*/
pre {
font-family: monospace, monospace; /* 1 */
font-size: 1em; /* 2 */
}
/* Text-level semantics
========================================================================== */
/**
* Remove the gray background on active links in IE 10.
*/
a {
background-color: transparent;
}
/**
* 1. Remove the bottom border in Chrome 57-
* 2. Add the correct text decoration in Chrome, Edge, IE, Opera, and Safari.
*/
abbr[title] {
border-bottom: none; /* 1 */
text-decoration: underline; /* 2 */
text-decoration: underline dotted; /* 2 */
}
/**
* Add the correct font weight in Chrome, Edge, and Safari.
*/
b,
strong {
font-weight: bolder;
}
/**
* 1. Correct the inheritance and scaling of font size in all browsers.
* 2. Correct the odd `em` font sizing in all browsers.
*/
code,
kbd,
samp {
font-family: monospace, monospace; /* 1 */
font-size: 1em; /* 2 */
}
/**
* Add the correct font size in all browsers.
*/
small {
font-size: 80%;
}
/**
* Prevent `sub` and `sup` elements from affecting the line height in
* all browsers.
*/
sub,
sup {
font-size: 75%;
line-height: 0;
position: relative;
vertical-align: baseline;
}
sub {
bottom: -0.25em;
}
sup {
top: -0.5em;
}
/* Embedded content
========================================================================== */
/**
* Remove the border on images inside links in IE 10.
*/
img {
border-style: none;
}
/* Forms
========================================================================== */
/**
* 1. Change the font styles in all browsers.
* 2. Remove the margin in Firefox and Safari.
*/
button,
input,
optgroup,
select,
textarea {
font-family: inherit; /* 1 */
font-size: 100%; /* 1 */
line-height: 1.15; /* 1 */
margin: 0; /* 2 */
}
/**
* Show the overflow in IE.
* 1. Show the overflow in Edge.
*/
button,
input { /* 1 */
overflow: visible;
}
/**
* Remove the inheritance of text transform in Edge, Firefox, and IE.
* 1. Remove the inheritance of text transform in Firefox.
*/
button,
select { /* 1 */
text-transform: none;
}
/**
* Correct the inability to style clickable types in iOS and Safari.
*/
button,
[type="button"],
[type="reset"],
[type="submit"] {
-webkit-appearance: button;
}
/**
* Remove the inner border and padding in Firefox.
*/
button::-moz-focus-inner,
[type="button"]::-moz-focus-inner,
[type="reset"]::-moz-focus-inner,
[type="submit"]::-moz-focus-inner {
border-style: none;
padding: 0;
}
/**
* Restore the focus styles unset by the previous rule.
*/
button:-moz-focusring,
[type="button"]:-moz-focusring,
[type="reset"]:-moz-focusring,
[type="submit"]:-moz-focusring {
outline: 1px dotted ButtonText;
}
/**
* Correct the padding in Firefox.
*/
fieldset {
padding: 0.35em 0.75em 0.625em;
}
/**
* 1. Correct the text wrapping in Edge and IE.
* 2. Correct the color inheritance from `fieldset` elements in IE.
* 3. Remove the padding so developers are not caught out when they zero out
* `fieldset` elements in all browsers.
*/
legend {
box-sizing: border-box; /* 1 */
color: inherit; /* 2 */
display: table; /* 1 */
max-width: 100%; /* 1 */
padding: 0; /* 3 */
white-space: normal; /* 1 */
}
/**
* Add the correct vertical alignment in Chrome, Firefox, and Opera.
*/
progress {
vertical-align: baseline;
}
/**
* Remove the default vertical scrollbar in IE 10+.
*/
textarea {
overflow: auto;
}
/**
* 1. Add the correct box sizing in IE 10.
* 2. Remove the padding in IE 10.
*/
[type="checkbox"],
[type="radio"] {
box-sizing: border-box; /* 1 */
padding: 0; /* 2 */
}
/**
* Correct the cursor style of increment and decrement buttons in Chrome.
*/
[type="number"]::-webkit-inner-spin-button,
[type="number"]::-webkit-outer-spin-button {
height: auto;
}
/**
* 1. Correct the odd appearance in Chrome and Safari.
* 2. Correct the outline style in Safari.
*/
[type="search"] {
-webkit-appearance: textfield; /* 1 */
outline-offset: -2px; /* 2 */
}
/**
* Remove the inner padding in Chrome and Safari on macOS.
*/
[type="search"]::-webkit-search-decoration {
-webkit-appearance: none;
}
/**
* 1. Correct the inability to style clickable types in iOS and Safari.
* 2. Change font properties to `inherit` in Safari.
*/
::-webkit-file-upload-button {
-webkit-appearance: button; /* 1 */
font: inherit; /* 2 */
}
/* Interactive
========================================================================== */
/*
* Add the correct display in Edge, IE 10+, and Firefox.
*/
details {
display: block;
}
/*
* Add the correct display in all browsers.
*/
summary {
display: list-item;
}
/* Misc
========================================================================== */
/**
* Add the correct display in IE 10+.
*/
template {
display: none;
}
/**
* Add the correct display in IE 10.
*/
[hidden] {
display: none;
}
-策略一:将Normalize.css作为你自己项目的基础CSS,自定义样式值以满足设计师的需求。
-策略二:引入Normalize.css源码并在从基础上构建,在必要的时候用到你自己写的CSS覆盖默认值。
结语
无论是从适用范畴还是实施上,Normalize.css与Reset都有着极大的不同。尝试一下这两种方法并看看到底哪一种更适合你的开发偏好是非常值得的。这个项目在Github上以开源的形式开发。任何人都能够提交问题报告或者是提交补丁。整个项目发展的过程对所有人都是可见的,而每一次改动的原因也都卸载commit信息中,这些都是有迹可循的