我会让自己适应52framework.com提供的内容。（HTML5、CSS3、JS 框架） 尽管看了网格教程视频和查看其他演示源代码，但我无法理解为什么框架使用<div class="clear"></div><!-- clear -->第 12 行的代码。
下面的代码地址是：http ://demo.52framework.com/demos/framework/grid.html
<body>
<div class="row">
<header>
<div class="logo col_7 col">52framework</div><!-- logo col_7 -->
<nav class="col_9 col">
<ul>
<li><a href="#navigation">navigation 1</a></li>
<li><a href="#navigation">navigation 2</a></li>
<li class="last"><a href="http://www.enavu.com">enavu network</a></li>
</ul>
</nav><!-- nav col_9 -->
<div class="clear"></div><!-- clear -->
</header>
</div><!-- row -->
...
下面的代码也来自同一来源，但正如您所见<div class="clear"></div><!-- clear -->，即使此处已完成更多分区，此处也未使用一段代码。
<!-- this section shows off the grid and how it can be used -->
<section class="row" id="grid">
<h2>Grid Framework</h2>
<div class="col col_8">
col_8
<div class="row">
<div class="col col_1">col_1</div>
<div class="col col_7">col_7
<div class="row">
<div class="col col_3">col_3</div>
<div class="col col_4">col_4</div>
</div><!-- row -->
</div>
</div><!-- row -->
</div><!-- col_8 -->
<div class="col col_8">
col_8
<div class="row">
<div class="col col_4">4</div>
<div class="col col_4">4</div>
</div><!-- row -->
</div><!-- col_8 -->
<div class="col_16 col" style="margin-top:15px;">
<div class="row">
<div class="col col_9">col_9</div>
<div class="col col_7">col_7</div>
</div><!-- row -->
</div><!-- col_16 -->
<div class="col_16 col">
<a href="http://www.52framework.com/documentation/" class="documentation">Grid Framework Documentation</a>
</div><!-- col_16 -->
</section><!-- row -->
相关CSS代码：
.clear { clear:both; display:block; overflow:hidden; visibility:hidden; height:0px;}
.col {
margin-left:10px; margin-right:10px;
display: inline;
overflow: hidden;
float: left;
position: relative;
}
.row{
width: 960px;
margin: 0 auto;
overflow: hidden;
}
.row .row {
margin: 0 -10px;
width: auto;
display: inline-block;
}
/* Column widths, and element width based on grid */
.col_1, .width_1 { width:40px; }
.col_2, .width_2 { width:100px; }
.col_3, .width_3 { width:160px; }
.col_4, .width_4 { width:220px; }
.col_5, .width_5 { width:280px; }
.col_6, .width_6 { width:340px; }
.col_7, .width_7 { width:400px; }
.col_8, .width_8 { width:460px; }
.col_9, .width_9 { width:520px; }
.col_10, .width_10 { width:580px; }
.col_11, .width_11 { width:640px; }
.col_12, .width_12 { width:700px; }
.col_13, .width_13 { width:760px; }
.col_14, .width_14 { width:820px; }
.col_15, .width_15 { width:880px; }
.col_16, .width_16 { width:940px; }