浏览器对body, h1这些标签，通常都有一个默认的css设置，而且不同的浏览器可能还不一样。例如
body {
display: block;
margin: 8px;
}
为了在不同浏览器上实现相同的显示效果，就需要处理这个问题，一般有两种方法：
- CSS Reset
- Normalize
CSS Reset
写一个css文件，在其中重新定义定义这些浏览默认设置，例如body{ margin: 0}
A CSS Reset (or “Reset CSS”) is a short, often compressed (minified) set of CSS rules that resets the styling of all HTML elements to a consistent baseline.
In case you didn’t know, every browser has its own default ‘user agent’ stylesheet, that it uses to make unstyled websites appear more legible. For example, most browsers by default make links blue and visited links purple, give tables a certain amount of border and padding, apply variable font-sizes to H1, H2, H3 etc. and a certain amount of padding to almost everything. Ever wondered why Submit buttons look different in every browser?
Obviously this creates a certain amount of headaches for CSS authors, who can’t work out how to make their websites look the same in every browser. (NB: article coming soon about why this is a false notion!)
Using a CSS Reset, CSS authors can force every browser to have all its styles reset to null, thus avoiding cross-browser differences as much as possible.
Eric Meyer’s “Reset CSS” 2.0
/* http://meyerweb.com/eric/tools/css/reset/
v2.0 | 20110126
License: none (public domain)
*/
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, 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,
article, aside, canvas, details, embed,
figure, figcaption, footer, header, hgroup,
menu, nav, output, ruby, section, summary,
time, mark, audio, video {
margin: 0;
padding: 0;
border: 0;
font-size: 100%;
font: inherit;
vertical-align: baseline;
}
/* HTML5 display-role reset for older browsers */
article, aside, details, figcaption, figure,
footer, header, hgroup, menu, nav, section {
display: block;
}
body {
line-height: 1;
}
ol, ul {
list-style: none;
}
blockquote, q {
quotes: none;
}
blockquote:before, blockquote:after,
q:before, q:after {
content: '';
content: none;
}
table {
border-collapse: collapse;
border-spacing: 0;
}
Normalize
比起Reset的简单粗暴，Normalize.css提供了一种更加优雅的处理方式
Normalize.css preserves useful defaults
Normalize.css corrects common bugs
Normalize.css doesn’t clutter your debugging tools
A common irritation when using resets is the large inheritance chain that is displayed in browser CSS debugging tools.
