DIV 上下居中用 line-height Html代码
<style type="text/css">
div.v-align {line-height: 200px;height: 200px;border: 1px solid red;}
</style>
<div class="v-align">垂直居中</div>
清除浏览器默认样式 1.用其他有名的库来清除（如：YUI)
2.自已清除 如：
* {padding: 0;margin:0;}
让A支持所有浏览器 Html代码
<style type="text/css">
a.agideo:link, a.agideo:visited {font-weight: bold;text-decoration: none;color: green;}
a.agideo:hover, a.agideo:active {font-weight: bold;text-decoration: none;color: red;}
</style>
<a href="http://www.agideo.com" class="agideo">捷道数码</a>
<style type="text/css">
a.google:hover, a.google:active {font-weight: bold;text-decoration: none;color: red;}
a.google:link, a.google:visited {font-weight: bold;text-decoration: none;color: green;}
</style>
<a href="http://www.google.com" class="google">Google</a>
A 伪类定义顺序记忆法 LoVe:HAte(爱恨)
IMG vertical-align
vertical-align : auto | baseline | sub | super | top | text-top | middle | bottom | text-bottom | length
baseline :默认值。将支持 valign 特性的对象的内容与基线对齐
sub 垂直对齐文本的下标
super 垂直对齐文本的上标
top : 将支持 valign 特性的对象的内容对象顶端对齐
text-top : 将支持 valign 特性的对象的文本与对象顶端对齐
middle : 将支持 valign 特性的对象的内容与对象中部对齐
bottom : 将支持 valign 特性的对象的内容与对象底端对齐
text-bottom : 将支持 valign 特性的对象的文本与对象顶端对齐
length : 由浮点数字和单位标识符组成的长度值 | 百分数。可为负数。定义由基线算起的偏移量。基线对于数值来说为0，对于百分数来说就是0%。请参阅 长度单位。目前IE尚未实现此参数
Html代码
<style type="text/css">
div.v-align {border: 1px solid red;line-height: 40px;float: left;font-size: 11px;height: 40px;}
div.v-align img.only-img {float:left;}
div.v-align.has-img {padding-top: 10px;height: 30px;}
div.v-align.has-img-and-text img.has-text {
vertical-align: -4px !important;vertical-align: middle;margin-top: -3px !important;margin-top: 0px;}
div.v-align.has-img-and-text {
padding-top: 0px !important;padding-top: 10px;height: 40px !important;height: 30px;}
</style>
<div class="v-align">正常</div>
<div class="v-align has-img"><img src="http://dl.iteye.com/upload/attachment/162320/1f89f269-580c-304b-975a-e6004b9893ce.png" class="only-img" /></div>
<div class="v-align has-img-and-text"><img src="./accept.png" align="absmiddle" class="has-text" />有图片有字</div>
垂直Margin 叠加 Html代码
<style tyep="text/css">
body, div {padding:0;margin:0;}
div, span {padding: 10px;margin: 10px;border: 10px solid #000;}
#div1 {background-color: red;}
#div2 {background-color: green;}
#div3 {background-color: blue;}
</style>
<div id="div1"><div>div1</div></div>
<div id="div2"><div>div2</div></div>
<div id="div3"><span>span1</span><span>span2</span></div>
Background position
Html代码
<style tyep="text/css">
body, div {padding:0;margin:0;}
div {border:1px solid #ccc;height: 200px;width: 300px;}
#div1 {background: url(http://dl.iteye.com/upload/attachment/162316/eee477c8-1fcc-3a41-874f-065f0d65a422.jpg) no-repeat 20px 20px;}
#div2 {background: urlhttp://dl.iteye.com/upload/attachment/162316/eee477c8-1fcc-3a41-874f-065f0d65a422.jpg) no-repeat 20% 20%;}
#div3 {background: url(http://dl.iteye.com/upload/attachment/162318/8be0e495-2d0a-3ec2-9f5f-7465eb8c23ae.jpg) no-repeat 20% 20%;}
</style>
<div id="div1">20px</div><br/>
<div id="div2">20%</div><br/>
<div id="div3">20%</div>
Float 占地问题 1.父子TAG都Float以父能包含子
Html代码
<style type="text/css">
div.parent {border: 1px solid red;width: 600px;float: left; }
div.child {border: 1px solid green;float: left;}
</style>
<div class="parent">
<div class="child">child</div>
<div class="child">child</div>
<div class="child">child</div>
</div>
Html代码
<style type="text/css">
div.parent {border: 1px solid red;width: 600px;float: left; }
div.child {border: 1px solid green;float: left;}
</style>
<div class="parent">
<div class="child">child</div>
<div class="child">child</div>
<div class="child">child</div>
</div>
2.最后一个子TAG后加一clear的无语义tag
Html代码
<style type="text/css">
div.parent {border: 1px solid red;width: 600px;}
div.child {border: 1px solid green;float: left;}
div.clear {clear: both;}
</style>
<div class="parent">
<div class="child">child</div>
<div class="child">child</div>
<div class="child">child</div>
<div class="clear"></div>
</div>
例子7:
Html代码
<style type="text/css">
div.parent {border: 1px solid red;width: 600px;}
div.child {border: 1px solid green;float: left;}
div.clear {clear: both;}
</style>
<div class="parent">
<div class="child">child</div>
<div class="child">child</div>
<div class="child">child</div>
<div class="clear"></div>
</div>
