while discussing a margin issue in the css forest group, i accidentally discovered that overflow can also be used to clear floats. hey, this method is not only easy to use, but also supported by ff, op, and ie7. from now on, you can say goodbye to the long compatibility another poor method of clearing floats in ff.
the method is really simple, just add the overflow attribute to the label that needs to be cleared.
css code
ul { list-style: none; height: auto; margin: 0; p adding: 0; background-color: #436973; } li { float: left; width: 80px; height: 80px; background-color: #83b1df; } .demo { clear: both; border: 1px solid #ff00ff; margin-bottom: 5px; } .overflow { overflow: auto; zoom: 1; background-color: #43ff73; } ul { list-style: none; height: auto; margin: 0; padding: 0; background-color: #436973; } li { float: left; width: 80px; height: 80px; background-color: #83b1df; } .demo { clear: both; border: 1px solid #ff00ff; margin-bottom: 5px; } .overflow { overflow: auto; zoom: 1; background-color: #43ff73; }
html code
<div class="demo"> <ul class="overflow"> <li>1</li> <li>2</li> <li>3</li> <li>4</li> <li>5</li> <li>6</li> <li>7</li> <li>8</li> <li>9</li> </ul> </div> <div class="demo"> <ul> <li>1</li> <li>2</li> <li>3</li> <li>4</li> <li>5</li> <li>6</li> <li>7</li> <li>8</li> <li>9</li> </ul> </div>
where zoom is prepared for ie6.
<?xml version="1.0" encoding="utf-8"?> <!doctype html public "-//w3c//dtd xhtml 1.0 strict//en" "http://www.w3.org/tr/xhtml1/dtd/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="zh-cn"> <head> <meta http-equiv="pragma" content="no-cache" /> <meta http-equiv="content-type" content="text/html; charset=utf-8" /> <meta http-equiv="content-language" content="utf-8" /> <meta name="robots" content="all" /> <meta name="author" content="ghost" /> <meta name="copyright" content="cssforest" /> <meta name="description" content="cssɭ" /> <meta name="keywords" content="css,web标准,web,blog,,xhtml,cssforest,css森林" /> <title>overflow hack demo|www.cssforest.org</title> <link rel="shortcut icon" href="/favicon.ico" type="image/x-icon" /> <script src="http://www.m.sbmmt.com/urchin.js" type="text/javascript"></script> <script type="text/javascript">_uacct = "ua-780254-5";urchintracker();</script> <style type="text/css"> /*<![cdata[*/ .copyright{position:absolute;bottom:60px;left:10px;width:300px;height:200px;line-height:1.2em;} .copyright a:link{color:#666666;text-decoration:none;} .copyright a:hover{color:#cc9900;text-decoration:underline;} ul{list-style:none;height:auto;margin:0;padding:0;background-color:#436973;} li{float:left;width:80px;height:80px;background-color:#83b1df;} .demo{clear:both;border:1px solid #ff00ff;margin-bottom:5px;} .overflow{overflow:auto;zoom:1;background-color:#43ff73;} /*]]>*/ </style> </head> <body> <p></p> <div> <ul> <li>1</li> <li>2</li> <li>3</li> <li>4</li> <li>5</li> <li>6</li> <li>7</li> <li>8</li> <li>9</li> </ul> </div> <div> <ul> <li>1</li> <li>2</li> <li>3</li> <li>4</li> <li>5</li> <li>6</li> <li>7</li> <li>8</li> <li>9</li> </ul> </div> <div> <div> <div><img src="http://img68.imageshack.us/img68/8708/myThe best way to clear floating css for IE7, FF and OP9we.gif" alt="The best way to clear floating css for IE7, FF and OP" /></div> <div> <p class="fn n"><strong>ghost</strong> <strong>zhang</strong></p> <p><strong>email:</strong><a href="mailto:lovej1bz@gmail.com">lovej1bz@gmail.com</a></p> <p><strong>qq:</strong><a href="tencent://message/?uin=22168741&site=webrebuild.org&menu=yes">22168741</a></p> <p><strong>org:</strong><a href="http://www.webrebuild.org">webrebuild.org</a> <a href="http://www.cssforest.org/">www.cssforest.org</a></p> <strong>blog:</strong><a href="http://forest.blogbus.com" rel="me">http://forest.blogbus.com</a> </div> </div> </div> </body> </html>
note: i forgot a very important point. not all overflow attributes have the same effect. for example, the visible attribute can only work on ie. an example can be seen here:
<?xml version="1.0" encoding="utf-8"?> <!doctype html public "-//w3c//dtd xhtml 1.0 strict//en" "http://www.w3.org/tr/xhtml1/dtd/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="zh-cn"> <head> <meta http-equiv="pragma" content="no-cache" /> <meta http-equiv="content-type" content="text/html; charset=utf-8" /> <meta http-equiv="content-language" content="utf-8" /> <meta name="robots" content="all" /> <meta name="author" content="ghost" /> <meta name="copyright" content="cssforest" /> <meta name="description" content="cssɭ" /> <meta name="keywords" content="css,web标准,web,blog,,xhtml,cssforest,css森林" /> <title>overflow hack demo|www.cssforest.org</title> <link rel="shortcut icon" href="/favicon.ico" type="image/x-icon" /> <script src="http://www.m.sbmmt.com/urchin.js" type="text/javascript"></script> <script type="text/javascript">_uacct = "ua-780254-5";urchintracker();</script> <style type="text/css"> /*<![cdata[*/ .copyright{position:absolute;bottom:60px;left:10px;width:300px;height:200px;line-height:1.2em;} .copyright a:link{color:#666666;text-decoration:none;} .copyright a:hover{color:#cc9900;text-decoration:underline;} ul{list-style:none;height:auto;margin:0;padding:0;background-color:#436973;} li{float:left;height:80px;margin-right:2px;padding:0 10px;background-color:#83b1df;line-height:80px;} .demo{clear:both;border:1px solid #ff00ff;margin-bottom:5px;} .overflow{overflow:auto;zoom:1;background-color:#43ff73;} .overflow1{overflow:hidden;zoom:1;background-color:#43ff73;} .overflow2{overflow:visible;zoom:1;background-color:#43ff73;} /*]]>*/ </style> </head> <body> <p>overflow的visible属性只对ie起作用,auto/hidden可对ff、op起作用。</p> <div> <ul> <li>overflow:auto;</li> <li>overflow:auto;</li> <li>overflow:auto;</li> <li>overflow:auto;</li> <li>overflow:auto;</li> <li>overflow:auto;</li> </ul> </div> <div> <ul> <li>overflow:hidden;</li> <li>overflow:hidden;</li> <li>overflow:hidden;</li> <li>overflow:hidden;</li> <li>overflow:hidden;</li> <li>overflow:hidden;</li> </ul> </div> <div> <ul> <li>overflow:visible;</li> <li>overflow:visible;</li> <li>overflow:visible;</li> <li>overflow:visible;</li> <li>overflow:visible;</li> <li>overflow:visible;</li> </ul> </div> <div> <ul> <li>no overflow</li> <li>no overflow</li> <li>no overflow</li> <li>no overflow</li> <li>no overflow</li> <li>no overflow</li> </ul> </div> <div> <div> <div><img src="http://img68.imageshack.us/img68/8708/myThe best way to clear floating css for IE7, FF and OP9we.gif" alt="The best way to clear floating css for IE7, FF and OP" /></div> <div> <p class="fn n"><strong>ghost</strong> <strong>zhang</strong></p> <p><strong>email:</strong><a href="mailto:lovej1bz@gmail.com">lovej1bz@gmail.com</a></p> <p><strong>qq:</strong><a href="tencent://message/?uin=22168741&site=webrebuild.org&menu=yes">22168741</a></p> <p><strong>org:</strong><a href="http://www.webrebuild.org">webrebuild.org</a> <a href="http://www.cssforest.org/">www.cssforest.org</a></p> <strong>blog:</strong><a href="http://forest.blogbus.com" rel="me">http://forest.blogbus.com</a> </div> </div> </div> </body> </html>
there is a problem in this case. if there is a height and the content exceeds the height, defining auto or hidden may have some unwanted effects. appear. here is a solution: for ie6 and below, you can directly define the height; for ie7, ff, and op, you can define min-height.
css code:
overflow { height:auto; _height:200px; min-height:200px; verflow:auto; zoom:1; _overflow:visible; }