初始化CSS
为什么要初始化CSS？
建站老手都知道，这是为了考虑到浏览器的兼容问题，其实不同浏览器对有些标签的默认值是不同的，如果没对CSS初始化往往会出现浏览器之间的页面差异。当然，初始化样式会对SEO有一定的影响，但鱼和熊掌不可兼得，但力求影响最小的情况下初始化。
最简单的初始化方法就是： * {padding: 0; margin: 0;} 。有很多人也是这样写的。这确实很简单，但有人就会感到疑问：*号这样一个通用符在编写代码的时候是快，但如果网站很大，CSS样式表文件很大，这样写的话，他会把所有的标签都初始化一遍，这样就大大的加强了网站运行的负载，会使网站加载的时候需要很长一段时间。
写过css的都知道每个网页引进的css首先都需要初始化，而出名的css reset有YUI css reset（QQ、淘宝等都出现他的影子），业内用的最多的还有Erik Meyer’s CSS Reset。
CSS初始化是指重设浏览器的样式。不同的浏览器默认的样式可能不尽相同，所以开发时的第一件事可能就是如何把它们统一。如果没对CSS初始化往往会出现浏览器之间的页面差异。每次新开发网站或新网页时候通过初始化CSS样式的属性，为我们将用到的CSS或html标签更加方便准确，使得我们开发网页内容时更加方便简洁，同时减少CSS代码量，节约网页下载时间。
通用初始化样式 1
body{
margin: 0;
padding: 0;
font-family: "微软雅黑";
overflow: hidden;
}
body,html{
-webkit-text-size-adjust: none;
width: 100%;
height: 100%;
}
*{
text-decoration: none;
list-style: none;
}
img{border: 0px;}
ul,li,dl,dd,dt,p,ol,h1,h2,h3,h4,h5{
font-size: 12px;
font-weight: 100;
padding: 0;
margin: 0;
}
.wrap{margin: 0 auto;}
.fl{float: left;}
.fr{float: right;}
.index{overflow: hidden;}
.clr{
clear:both;
height:0px;
width:100%;
font-size:1px;
line-height:0px;
visibility:hidden;
overflow:hidden;
}
.pointer{cursor:pointer;}
a,input,button{ outline:none; }
::-moz-focus-inner{border:0px;}
/*a:link {color:#0f0;text-decoration:none;}
a:visited {color: #FFFF00; text-decoration:none;}
a:hover {color: #00FF00; text-decoration:underline;}
a:active {color: #0000FF; text-decoration:underline;}*/
a{color: #000;}
.wrapper{clear: both;width: 100%;}
table { border-collapse:collapse; }
word-break:break-all /*文字换行*/
/*white-space:nowrap 文字不换行*/
/*默认滚动条样式修改ie9 google Firefox 等高版本浏览器有效*/
/*::selection {background: #D03333;color: white;text-shadow: none;}
::-webkit-scrollbar-track-piece{width:10px;background-color:#f2f2f2}
::-webkit-scrollbar{width:10px;height:6px}
::-webkit-scrollbar-thumb{height:50px;background-color:rgba(0,0,0,.3);}
::-webkit-scrollbar-thumb:hover{background:#cc0000}*/
/*渐变*/
/*background-image: -moz-linear-gradient(top, #8fa1ff, #3757fa);
background-image: -webkit-gradient(linear, left top, left bottom, color-stop(0, #ff4f02), color-stop(1, #8f2c00));
Saf4+, Chrome filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#c6ff00', endColorstr='#538300', GradientType='0'); IE*/
另一种通用化样式
/* CSS Document */ html, body, div, span, object, iframe,h1, h2, h3, h4, h5, h6, p, blockquote, pre,abbr, address, cite, code,del, dfn, em, img, ins,kbd, q, samp,small, strong, sub, sup, var,b, i,dl, dt, dd, ol, ul, li,fieldset, form, label, legend,table, caption, tbody, tfoot,thead,tr, th, td,article, aside, canvas, details, figcaption, figure, footer, header, hgroup, menu, nav, section, summary,time, mark, audio, video { margin:0; padding:0; border:0; outline:0; font-size:100%; vertical-align:baseline; background:transparent; outline-style:none;/*FF*/ } body { line-height:1; } a{ margin:0; padding:0; border:0; font-size:100%; vertical-align:baseline; background:transparent; } a:hover,a:focus{ text-decoration:none; bblr:expression(this.onFocus=this.blur());/*IE*/ outline-style:none;/*FF*/ } table { border-collapse:collapse; border-spacing:0; } input, select { vertical-align:middle; } /*css为clearfix，清除浮动*/ .clearfix::before, .clearfix::after{ content: ""; height: 0; line-height: 0; display: block; visibility: hidden; clear: both; } .clearfix:after{clear:both;} .clearfix{ *zoom:1;/*IE/7/6*/ }
雅虎工程师提供的CSS初始化示例代码
body,div,dl,dt,dd,ul,ol,li,h1,h2,h3,h4,h5,h6,pre,code,form,fieldset,legend,input,button,textarea,p,blockquote,th,td { margin:0; padding:0; }
body { background:#fff; color:#555; font-size:14px; font-family: Verdana, Arial, Helvetica, sans-serif; }
td,th,caption { font-size:14px; }
h1, h2, h3, h4, h5, h6 { font-weight:normal; font-size:100%; }
address, caption, cite, code, dfn, em, strong, th, var { font-style:normal; font-weight:normal;}
a { color:#555; text-decoration:none; }
a:hover { text-decoration:underline; }
img { border:none; }
ol,ul,li { list-style:none; }
input, textarea, select, button { font:14px Verdana,Helvetica,Arial,sans-serif; }
table { border-collapse:collapse; }
html {overflow-y: scroll;}
.clearfix:after {content: "."; display: block; height:0; clear:both; visibility: hidden;}
.clearfix { *zoom:1; }
腾讯官网 样式初始化
body,ol,ul,h1,h2,h3,h4,h5,h6,p,th,td,dl,dd,form,fieldset,legend,input,textarea,select{margin:0;padding:0} body{font:12px"宋体","Arial Narrow",HELVETICA;background:#fff;-webkit-text-size-adjust:100%;} a{color:#2d374b;text-decoration:none} a:hover{color:#cd0200;text-decoration:underline} em{font-style:normal} li{list-style:none} img{border:0;vertical-align:middle} table{border-collapse:collapse;border-spacing:0} p{word-wrap:break-word} 新浪官网 样式初始化 body,ul,ol,li,p,h1,h2,h3,h4,h5,h6,form,fieldset,table,td,img,div{margin:0;padding:0;border:0;} body{background:#fff;color:#333;font-size:12px; margin-top:5px;font-family:"SimSun","宋体","Arial Narrow";} ul,ol{list-style-type:none;} select,input,img,select{vertical-align:middle;} a{text-decoration:none;} a:link{color:#009;} a:visited{color:#800080;} a:hover,a:active,a:focus{color:#c00;text-decoration:underline;}
淘宝官网 样式初始化
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/1.5tahoma, 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:couriernew, 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; }
网易官网 样式初始化
html {overflow-y:scroll;}
body {margin:0; padding:29px00; font:12px"\5B8B\4F53",sans-serif;background:#ffffff;}
div,dl,dt,dd,ul,ol,li,h1,h2,h3,h4,h5,h6,pre,form,fieldset,input,textarea,blockquote,p{padding:0; margin:0;}
table,td,tr,th{font-size:12px;}
li{list-style-type:none;}
img{vertical-align:top;border:0;}
ol,ul {list-style:none;}
h1,h2,h3,h4,h5,h6{font-size:12px; font-weight:normal;}
address,cite,code,em,th {font-weight:normal; font-style:normal;}
下面顺便给出admin10000.com 的html模板，用于每次新开发页面使用。
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" lang="zh-cn"> <head> <title>网站标题 - Admin10000.com </title> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <meta http-equiv="Content-Language" content="zh-CN" /> <meta name="Author" content="网页作者" /> <meta name="Copyright" content="网站版权" /> <meta name="keywords" content="网站关键字" /> <meta name="description" content="网站描述" /> <link rel="Shortcut Icon" href="网站.ico图标路径" /> <link type="text/css" rel="stylesheet" href="CSS文件路径" /> <script type="text/javascript" src="JS文件路径"></script> </head> <body> </body> </html>
原文地址： https://www.cnblogs.com/Gavinzhong/p/6995328.html
https://blog.csdn.net/Dj_Fairy/article/details/78748329
一些其他的初始化样式
1.
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; }
body { font-size:12px; color:#666; font-family:Verdana, Microsoft YaHei, Simsun; background:#fff; line-height:24px; }
fieldset, img { border:0; }
ol, ul { list-style:none; }
h1, h2, h3, h4, h5, h6{ font-size:100%; }
em { font-style:normal; }
input, button, select, textarea { outline:none; }
textarea { resize:none; } //禁用了文本的拖拉，尤其在谷歌下
p{ text-align:justify; text-justify:distribute;} //为了使文本段落左右两边对齐
a { color: #666; text-decoration:none; }
a:hover { color: #f60; text-decoration:none; }
2.
html, body, div, span, applet, object, iframe,h1, h2, h3, h4, h5, h6, p, blockquote, pre, a, address, code, em, img, strong, dl, dt, dd, ol, ul, li, fieldset, form, label, legend, table, tbody, tr, th, td { margin: 0; padding: 0; border: 0; outline: 0; } 意思是页面中的所有html标签、body标签、div标签、span标签.......tr标签、th标签、td标签的填充、边距、边框、外边线都为0，其中outline是ie不支持，在ff下是外边线，比如用它可以改变元素聚焦时候的虚线样式。
