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在当今网页设计/开发实践中，使用CSS来为语义化的(X)HTML标记添加样式风格是重要的关键。在设计师们的梦想中都存在着这样的一个完美世界:所有的浏览器都能够理解和适用多有CSS规则，并且呈现相同的视觉效果(没有兼容性问题)。但是，我们并没有生活在这个完美的世界，现实中发生的失窃却总是恰恰相反，很多CSS样式在不同的浏览器中有着不同的解释和呈现。
当今流行的浏览器(如:Firefox、Opera、Internet Explorer、Chrome、Safari等等)中，有一些都是以自己的方式去理解CSS规范，这就会导致有的浏览器对CSS的解释与设计师的CSS定义初衷相冲突，使得网页的样子在某些浏览器下能正确按照设计师的想法显示，但有些浏览器却并没有按照设计师想要的样子显示出来，这就导致浏览器的兼容性问题。更糟的是，有的浏览器完全无视CSS的一些声明和属性。
正因为上述冲突和问题依然存在于这个”不完美的世界”，所以一些设计师想到了一种避免浏览器兼容性问题的方法，那就是CSS Reset，什么是CSS Reset？我们可以把它叫做CSS重设，也有人叫做CSS复位、默认CSS、CSS重置等。CSS重设就是由于各种浏览器解释CSS样式的初始值有所不同，导致设计师在没有定义某个CSS属性时，不同的浏览器会按照自己的默认值来为没有定义的样式赋值，所以我们要先定义好一些CSS样式，来让所有浏览器都按照同样的规则解释CSS，这样就能避免发生这种问题。
* { padding: 0; margin: 0;} 这是最普遍最简单的CSS重设，将所有元素的padding和margin值都设为0，可以避免一些浏览器在理解这两个属性默认值上的”分歧”。
* { padding: 0; margin: 0; border: 0;} 这是在上一个重设的基础上添加了对border属性的重设，初始值为0的确能避免一些问题。
* { outline: 0; padding: 0; margin: 0; border: 0;} 在前两个的基础上添加了outline属性的重设，防止一些冲突。
* { vertical-align: baseline; font-weight: inherit; font-family: inherit; font-style: inherit; font-size: 100%; outline: 0; padding: 0; margin: 0; border: 0;} 该CSS重设方法出自Perishable Press，这是他常用的方法。
html, body { padding: 0; margin: 0; }html { font-size:1em;} body { font-size:100%;} a img, :link img, :visited img { border:0px;} 这个重设方法将html和body下元素的padding和margin都设为0，并分别为html标签和body标签下的所有元素设置了初始的字体大小，最重要的是把有链接的图片的默认边框去掉了。
* { vertical-align: baseline; font-family: inherit; font-style: inherit; font-size: 100%; border: none; padding: 0; margin: 0; }body { padding: 5px;} h1, h2, h3, h4, h5, h6, p, pre, blockquote, form, ul, ol, dl { margin: 20px 0;}li, dd, blockquote { margin-left: 40px;} table { border-collapse: collapse; border-spacing: 0; }
body, div, dl, dt, dd, ul, ol, li, h1, h2, h3, h4, h5, h6, pre, form, fieldset, input, p, blockquote, table, th, td, embed, object { padding: 0; margin: 0; }table { border-collapse: collapse; border-spacing: 0;} fieldset, img, abbr { border: 0;}address, caption, cite, code, dfn, em, h1, h2, h3, h4, h5, h6, strong, th, var { font-weight: normal; font-style: normal;}ul { list-style: none;}caption, th { text-align: left;}h1, h2, h3, h4, h5, h6 { font-size: 1.0em;}q:before, q:after { content: ”;}a, ins { text-decoration: none;}
body,div,dl,dt,dd,ul,ol,li,h1,h2,h3,h4,h5,h6,pre, form,fieldset,input,textarea,p,blockquote,th,td { padding: 0; margin: 0; } table { border-collapse: collapse; border-spacing: 0; } fieldset,img { border: 0; } address,caption,cite,code,dfn,em,strong,th,var { font-weight: normal; font-style: normal; } ol,ul { list-style: none; } caption,th { text-align: left; } h1,h2,h3,h4,h5,h6 { font-weight: normal; font-size: 100%; } q:before,q:after { content:”; } abbr,acronym { border: 0; }七.Eric Meyer’s CSS Resethtml, body, div, span, applet, object, iframe, table, caption, tbody, tfoot, thead, tr, th, td, del, dfn, em, font, img, ins, kbd, q, s, samp, small, strike, strong, sub, sup, tt, var, h1, h2, h3, h4, h5, h6, p, blockquote, pre, a, abbr, acronym, address, big, cite, code, dl, dt, dd, ol, ul, li, fieldset, form, label, legend { vertical-align: baseline; font-family: inherit; font-weight: inherit; font-style: inherit; font-size: 100%; outline: 0; padding: 0; margin: 0; border: 0; } :focus { outline: 0; } body { background: white; line-height: 1; color: black; } ol, ul { list-style: none; } table { border-collapse: separate; border-spacing: 0; } caption, th, td { font-weight: normal; text-align: left; } blockquote:before, blockquote:after, q:before, q:after { content: “”; } blockquote, q { quotes: “” “”; }
body, div, dl, dt, dd, ul, ol, li, h1, h2, h3, h4, h5, h6, pre, form, fieldset, input, textarea, p, blockquote, th, td { padding: 0; margin: 0;} fieldset, img { border: 0;}table { border-collapse: collapse; border-spacing: 0;}ol, ul { list-style: none;}address, caption, cite, code, dfn, em, strong, th, var { font-weight: normal; font-style: normal;}caption, th { text-align: left;}h1, h2, h3, h4, h5, h6 { font-weight: normal; font-size: 100%;}q:before, q:after { content: ”;}abbr, acronym { border: 0;} 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, font, img, ins, kbd, q, s, samp, small, strike, strong, sub, sup, tt, var, dl, dt, dd, ol, ul, li, fieldset, form, label, legend, table, caption, tbody, tfoot, thead, tr, th, td { margin: 0; padding: 0; border: 0; outline: 0; font-weight: inherit; font-style: inherit; font-size: 100%; font-family: inherit; vertical-align: baseline; } :focus { outline: 0;} a, a:link, a:visited, a:hover, a:active{ text-decoration:none} table { border-collapse: separate; border-spacing: 0;} th, td { text-align: left; font-weight: normal;} img, iframe { border: none; text-decoration:none;} ol, ul { list-style: none;} input, textarea, select, button { font-size: 100%; font-family: inherit;} select { margin: inherit;} hr { margin: 0; padding: 0; border: 0; color: #000; background-color: #000; height: 1px} * { vertical-align: baseline; font-family: inherit; font-style: inherit; font-size: 100%; border: none; padding: 0; margin: 0; } body { padding: 5px; } h1, h2, h3, h4, h5, h6, p, pre, blockquote, form, ul, ol, dl { margin: 20px 0; } li, dd, blockquote { margin-left: 40px; } table { border-collapse: collapse; border-spacing: 0; } :link,:visited { text-decoration:none } ul,ol { list-style:none } h1,h2,h3,h4,h5,h6,pre,code { font-size:1em; } ul,ol,li,h1,h2,h3,h4,h5,h6,pre,form,body,html,p,blockquote,fieldset,input { margin:0; padding:0 } a img,:link img,:visited img { border:none } address { font-style:normal } html, body, form, fieldset { margin: 0; padding: 0; font: 100%/120% Verdana, Arial, Helvetica, sans-serif; } h1, h2, h3, h4, h5, h6, p, pre, blockquote, ul, ol, dl, address { margin: 1em 0; padding: 0; } li, dd, blockquote { margin-left: 1em; } form label { cursor: pointer; } fieldset { border: none; } input, select, textarea { font-size: 100%; font-family: inherit; } * { margin: 0; padding: 0; border: none; } html { font: 62.5% “Lucida Grande”, Lucida, Verdana, sans-serif; text-shadow: #000 0px 0px 0px; } ul { list-style: none; list-style-type: none; } h1, h2, h3, h4, h5, h6, p, pre, blockquote, ul, ol, dl, address { font-weight: normal; margin: 0 0 1em 0; } cite, em, dfn { font-style: italic; } sup { position: relative; bottom: 0.3em; vertical-align: baseline; } sub { position: relative; bottom: -0.2em; vertical-align: baseline; } li, dd, blockquote { margin-left: 1em; } code, kbd, samp, pre, tt, var, input[type='text'], textarea { font-size: 100%; font-family: monaco, “Lucida Console”, courier, mono-space; } del { text-decoration: line-through; } ins, dfn { border-bottom: 1px solid #ccc; } small, sup, sub { font-size: 85%; } abbr, acronym { text-transform: uppercase; font-size: 85%; letter-spacing: .1em; border-bottom-style: dotted; border-bottom-width: 1px; } a abbr, a acronym { border: none; } sup { vertical-align: super; } sub { vertical-align: sub; } h1 { font-size: 2em; } h2 { font-size: 1.8em; } h3 { font-size: 1.6em; } h4 { font-size: 1.4em; } h5 { font-size: 1.2em; } h6 { font-size: 1em; } a, a:link, a:visited, a:hover, a:active { outline: 0; text-decoration: none; } a img { border: none; text-decoration: none; } img { border: none; text-decoration: none; } label, button { cursor: pointer; } input:focus, select:focus, textarea:focus { background-color: #FFF; } fieldset { border: none; } .clear { clear: both; } .float-left { float: left; } .float-right { float: right; } body { text-align: center; } #wrapper { margin: 0 auto; text-align: left; } 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, font, img, ins, kbd, q, s, samp, small, strike, strong, sub, sup, tt, var, dl, dt, dd, ol, ul, li, fieldset, form, label, legend, table, caption, tbody, tfoot, thead, tr, th, td, center, u, b, i { margin: 0; padding: 0; border: 0; outline: 0; font-weight: normal; font-style: normal; font-size: 100%; font-family: inherit; vertical-align: baseline } body { line-height: 1 } :focus { outline: 0 } ol, ul { list-style: none } table { border-collapse: collapse; border-spacing: 0 } blockquote:before, blockquote:after, q:before, q:after { content: “” } blockquote, q { quotes: “” “” } input, textarea { margin: 0; padding: 0 } hr { margin: 0; padding: 0; border: 0; color: #000; background-color: #000; height: 1px } 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, font, img, ins, kbd, q, s, samp, small, strike, strong, sub, sup, tt, var, dl, dt, dd, ol, ul, li, fieldset, form, label, legend, table, caption, tbody, tfoot, thead, tr, th, td { margin: 0; padding: 0; border: 0; outline: 0; font-weight: inherit; font-style: inherit; font-size: 100%; font-family: inherit; vertical-align: baseline; } :focus { outline: 0; } table { border-collapse: separate; border-spacing: 0; } caption, th, td { text-align: left; font-weight: normal; } a img, iframe { border: none; } ol, ul { list-style: none; } input, textarea, select, button { font-size: 100%; font-family: inherit; } select { margin: inherit; } /* Fixes incorrect placement of numbers in ol’s in IE6/7 */ ol { margin-left:2em; } /* == clearfix == */ .clearfix:after { content: “.”; display: block; height: 0; clear: both; visibility: hidden; } .clearfix {display: inline-block;} * html .clearfix {height: 1%;} .clearfix {display: block;} 这15套重设方法其实都是有共同点的，也许有的实现方法不同，但大部分都是同一个目的，就是为了让更多的浏览器能显示同样的效果。有了这些CSS重设作为资料和参考，也许会对你的工作有所帮助甚至提高效率，但是，毕竟这些重设都是别人写的，你完全也可以为自己量身定制一套CSS重设。 转载地址：http://sbjvi.baihongyu.com/