为什么初始化css?
考虑到浏览器兼容性问题，不同浏览器对标签的默认值是不同的
通用初始化样式
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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
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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
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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
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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
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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。
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<!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>