怎么让一个DIV浮动在另一个DIV上面

如何让一个DIV浮动在另一个DIV上面

 

直接上DEMO了

<span style="color: #0000ff"><span style="color: #ff00ff">DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"</span><span style="color: #0000ff">></span><span style="color: #0000ff"><span style="color: #800000">meta </span><span style="color: #ff0000">http-equiv</span><span style="color: #0000ff">="Content-Type"</span><span style="color: #ff0000"> content</span><span style="color: #0000ff">="text/html; charset=gb2312"</span> <span style="color: #0000ff">/></span><span style="color: #0000ff"><span style="color: #800000">style </span><span style="color: #ff0000">type</span><span style="color: #0000ff">="text/css"</span><span style="color: #0000ff">></span><span style="color: #800000; background-color: #f5f5f5"><!-- .d1 </span><span style="color: #000000; background-color: #f5f5f5">{</span><span style="color: #ff0000; background-color: #f5f5f5">        position</span><span style="color: #000000; background-color: #f5f5f5">:</span><span style="color: #0000ff; background-color: #f5f5f5">absolute</span><span style="color: #000000; background-color: #f5f5f5">;</span><span style="color: #ff0000; background-color: #f5f5f5">        top</span><span style="color: #000000; background-color: #f5f5f5">:</span><span style="color: #0000ff; background-color: #f5f5f5">20px</span><span style="color: #000000; background-color: #f5f5f5">;</span><span style="color: #ff0000; background-color: #f5f5f5">        left</span><span style="color: #000000; background-color: #f5f5f5">:</span><span style="color: #0000ff; background-color: #f5f5f5">20px</span><span style="color: #000000; background-color: #f5f5f5">;</span><span style="color: #ff0000; background-color: #f5f5f5">        width</span><span style="color: #000000; background-color: #f5f5f5">:</span><span style="color: #0000ff; background-color: #f5f5f5">200px</span><span style="color: #000000; background-color: #f5f5f5">;</span><span style="color: #ff0000; background-color: #f5f5f5">        height</span><span style="color: #000000; background-color: #f5f5f5">:</span><span style="color: #0000ff; background-color: #f5f5f5">200px</span><span style="color: #000000; background-color: #f5f5f5">;</span><span style="color: #ff0000; background-color: #f5f5f5">        background</span><span style="color: #000000; background-color: #f5f5f5">:</span><span style="color: #0000ff; background-color: #f5f5f5">red        </span><span style="color: #000000; background-color: #f5f5f5">}</span><span style="color: #800000; background-color: #f5f5f5">.d2 </span><span style="color: #000000; background-color: #f5f5f5">{</span><span style="color: #ff0000; background-color: #f5f5f5">        width</span><span style="color: #000000; background-color: #f5f5f5">:</span><span style="color: #0000ff; background-color: #f5f5f5">500px</span><span style="color: #000000; background-color: #f5f5f5">;</span><span style="color: #ff0000; background-color: #f5f5f5">        height</span><span style="color: #000000; background-color: #f5f5f5">:</span><span style="color: #0000ff; background-color: #f5f5f5">100px</span><span style="color: #000000; background-color: #f5f5f5">;</span><span style="color: #ff0000; background-color: #f5f5f5">        background</span><span style="color: #000000; background-color: #f5f5f5">:</span><span style="color: #0000ff; background-color: #f5f5f5">blue</span><span style="color: #000000; background-color: #f5f5f5">;</span>        <span style="color: #000000; background-color: #f5f5f5">}</span><span style="color: #800000; background-color: #f5f5f5">--></span><span style="color: #0000ff"></span><span style="color: #800000">style</span><span style="color: #0000ff">></span><span style="color: #0000ff"><span style="color: #800000">div </span><span style="color: #ff0000">class</span><span style="color: #0000ff">="d1"</span><span style="color: #0000ff">></span><span style="color: #800000">div</span><span style="color: #0000ff">></span><span style="color: #0000ff"><span style="color: #800000">div </span><span style="color: #ff0000">class</span><span style="color: #0000ff">="d2"</span><span style="color: #0000ff">></span><span style="color: #800000">div</span><span style="color: #0000ff">></span></span></span></span></span></span>