css双浮动如何智能调节父标签的高度

如题，我只能做到根据第一个浮动调节父标签的高度，双浮动的话，如果第二个浮动比第一个高的话，就会溢出。不要让我隐藏第二个浮动溢出的部分，我需要能够全部显示

几种解决办法
http://www.divcss5.com/jiqiao/j612.shtml

参考A new micro clearfix hack
使用在父级元素使用clearfix样式

/**
 * For modern browsers
 * 1. The space content is one way to avoid an Opera bug when the
 *    contenteditable attribute is included anywhere else in the document.
 *    Otherwise it causes space to appear at the top and bottom of elements
 *    that are clearfixed.
 * 2. The use of `table` rather than `block` is only necessary if using
 *    `:before` to contain the top-margins of child elements.
 */
.cf:before,
.cf:after {
    content: " "; /* 1 */
    display: table; /* 2 */
}

.cf:after {
    clear: both;
}

/**
 * For IE 6/7 only
 * Include this rule to trigger hasLayout and contain floats.
 */
.cf {
    *zoom: 1;
}

当然，网上还有其他的跨浏览器的clearfix的写法，可以自己搜一下