Browser default tag style summary and css initialization program
html中的大部分的标签都有一些糟糕的样式，有的是标签天然自带的，有的是浏览器默认设置的，我们在写网页时，这些默认的样式就会时不时的跳出来捣一下乱，搞得我们很是无奈。所以成手在写css样式时，一般都会在开头写一段初始化程序，来去掉这些默认样式，比如最简单的方法就是使用*{margin：0；padding：0；}。但是通常我们很少使用这种方法，因为通配符*的效率极低。那我们应该使用哪种方法呢，下面博主就来为大家介绍一些常用的方法。
一、浏览器默认样式总结
在介绍初始化程序之前，我们先了解一下都有那些标签被设置了哪些默认样式，只有了解清楚了这些，我们才能更好的对标签样式初始化。
（一）、标签自带样式
//块级元素
html, body, div,ol, p, ul, h1, h2,h3,h4,h5, h6,
address,blockquote, form,
dd,dl, dt, fieldset, frame, frameset,noframes,center, dir, hr, menu, pre
{ display: block }
//列表元素类
li{ display:list-item }
ol{list-style-type: decimal }
ol ul, ul ol,ul ul, ol ol { margin-top: 0; margin-bottom: 0 }
ol, ul{ margin-left: 40px }
//预格式文本类
i, cite, em,var, address{ font-style: italic }
big{ font-size:1.17em }
small, sub, sup{ font-size: .83em }
sub{ vertical-align:sub }
sup{ vertical-align:super }
s, strike, del{ text-decoration: line-through }
u, ins{ text-decoration:underline }
//标题类
h1{ font-size:2em; margin: .67em 0 }
h2{ font-size:1.5em; margin: .75em 0 }
h3{ font-size:1.17em; margin: .83em 0 }
h4, p,blockquote, ul,fieldset, form,ol, dl, dir,menu { margin: 1.12em 0}
h5 { font-size:.83em; margin: 1.5em 0 }
h6{ font-size:.75em; margin: 1.67em 0 }
h1, h2, h3, h4,h5, h6, b,strong { font-weight: bolder }
//伪类
br:before{ content: ”\A” }
:before, :after{ white-space: pre-line }
:link, :visited { text-decoration: underline }
:focus{ outline: thin dotted invert }
//表格类
table{ display: table }
tr{ display:table-row }
thead{ display:table-header-group }
tbody{ display:table-row-group }
tfoot{ display:table-footer-group }
col{ display:table-column }
colgroup{ display:table-column-group }
td, th{ display: table-cell;}
caption{ display: table-caption }
th{font-weight: bolder; text-align: center }
caption{ text-align: center }
table{ border-spacing: 2px;}
thead, tbody,tfoot { vertical-align:middle }
td, th { vertical-align:inherit }
//其它元素
head{ display: none }
body{ margin: 8px;line-height: 1.12 }
button, textarea,input, object,select { display:inline-block;}
blockquote{ margin-left: 40px;margin-right: 40px }
pre, tt, code,kbd, samp { font-family: monospace }
pre{ white-space: pre}
hr{ border: 1px inset }
center{ text-align: center }
abbr, acronym{ font-variant: small-caps; letter-spacing:0.1em }
BDO[DIR="ltr"] { direction: ltr; unicode-bidi:bidi-override }
BDO[DIR="rtl"] { direction: rtl; unicode-bidi:bidi-override }
/*定义BDO元素当其属性为DIR="ltr/rtl"时的默认文本读写显示顺序*/
*[DIR="ltr"]{ direction: ltr;unicode-bidi: embed }
*[DIR="rtl"] { direction: rtl;unicode-bidi: embed }
/*定义任何元素当其属性为DIR="rtl/rtl"时的默认文本读写显示顺序*/
@media print {
h1{page-break-before: always }
h1, h2, h3,h4, h5, h6 { page-break-after: avoid }
ul, ol, dl{ page-break-before: avoid }
} /*定义标题和列表默认的打印样式*/
（二）、浏览默认样式类
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。
1.页边距
IE默认为10px，通过body的margin属性设置
FF默认为8px，通过body的padding属性设置
2.段间距
IE默认为19px，通过p的margin-top属性设置
FF默认为1.12em，通过p的margin-bottom属性设
3.标题样式
h1~h6默认加粗显示：font-weight:bold;。
默认大小请参上表
还有是这样的写的
<span style="color: #000000;">h1 {font-size:xx-large;}
h2 {font-size:x-large;}
h3 {font-size:large;}
h4 {font-size:medium;}
h5 {font-size:small;}
h6 {font-size:x-small;}</span> 4.列表样式
IE默认为40px，通过ul、ol的margin属性设置
FF默认为40px，通过ul、ol的padding属性设置
dl无缩进，但起内部的说明元素dd默认缩进40px，而名称元素dt没有缩进。
5.元素居中
IE默认为text-align:center;
FF默认为margin-left:auto;margin-right:auto;
6.超链接样式
a 样式默认带有下划线，显示颜色为蓝色，被访问过的超链接变紫色
7.鼠标样式
IE默认为cursor:hand;
FF默认为cursor:pointer;该声明在IE中也有效
8.图片链接样式
IE默认为紫色2px的边框线
FF默认为蓝色2px的边框线
二、css初始化程序
博主总结了一些初始化的代码，博友们可以参考一下，具体使用时可以适当地删减一些。
<span style="color: #000000;">@charset "UTF-8";
/*css 初始化 */
html, body, ul, li, ol, dl, dd, dt, p, h1, h2, h3, h4, h5, h6, form, fieldset, legend, img {
margin: 0;
padding: 0;
}
fieldset, img, input, button {
border: none;
padding: 0;
margin: 0;
outline-style: none;
}
ul, ol {
list-style: none;
}
input {
padding-top: 0;
padding-bottom: 0;
font-family: "SimSun", "宋体";
}
select, input {
vertical-align: middle;
}
select, input, textarea {
font-size: 12px;
margin: 0;
}
textarea {
resize: none;
}
/*防止拖动*/
img {
border: 0;
vertical-align: middle;
}
/* 去掉图片低测默认的3像素空白缝隙*/
table {
border-collapse: collapse;
}
body {
font: 12px/150% Arial, Verdana, "\5b8b\4f53";
color: #666;
background: #fff
}
h1, h2, h3, h4, h5, h6 {
text-decoration: none;
font-weight: normal;
font-size: 100%;
}
s, i, em {
font-style: normal;
text-decoration: none;
}</span>
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