最常用

* {
  -webkit-box-sizing: border-box;
     -moz-box-sizing: border-box;
          box-sizing: border-box;
}
*:before,
*:after {
  -webkit-box-sizing: border-box;
     -moz-box-sizing: border-box;
          box-sizing: border-box;
}
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: "Arial", "Microsoft YaHei", "黑体", "宋体", 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;
    vertical-align: middle;
}
ol, ul, li {
    list-style: none;
}
input, textarea, select, button {
    font: 14px "Arial", "Microsoft YaHei", "黑体", "宋体", sans-serif;
}
table {
    border-collapse: collapse;
}
html {
    overflow-y: scroll;
}
.clearfix:before,
.clearfix:after {
    content: " ";
    display: inline-block;
    height: 0;
    clear: both;
    visibility: hidden;
}
.clearfix {
    *zoom: 1;
}

/*公共类*/
.fl {
    float: left
}
.fr {
    float: right
}
.al {
    text-align: left
}
.ac {
    text-align: center
}
.ar {
    text-align: right
}
.hide {
    display: none
}

雅虎代码初始化：

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: "Arial","Microsoft YaHei","黑体","宋体",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 "Arial","Microsoft YaHei","黑体","宋体",sans-serif; }
table { border-collapse:collapse; }
html {overflow-y: scroll;} 

.clearfix:after {content: "."; display: block; height:0; clear:both; visibility: hidden;}
.clearfix { *zoom:1; }/*公共类*/
.fl { float:left}
.fr {float:right}
.al {text-align:left}
.ac {text-align:center}
.ar {text-align:right}
.hide {display:none}

腾讯QQ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;}