<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>同辈元素定位方式相同,且无z-index设置时,html靠后者居上。</title> </head> <style type="text/css"> div { font:12px/1.5 arial;} div strong { color:#fff; background:#036; display:inline-block;} h3 strong { color:#f00;} /*--- 定义方块外形 ---*/ .div1, .div2 { height:70px; 150px; background:#cff; border:1px solid #036; } .div2 { margin-top:-20px; margin-left:75px; padding-top:30px; height:40px; } td{ height:200px; 350px; border:solid 1px #C69;} </style> <body> <h3> 法则一:同辈元素各种情况比较<br />公共样式:<br /> <span style="color:#F6C"> .div1,<br /> .div2 {<br /> height:70px;<br /> 150px;<br /> background:#cff;<br /> border:1px solid #036;<br /> }<br /> .div2 {<br /> margin-top:-20px;<br /> margin-left:75px;<br /> padding-top:30px;<br /> height:40px;<br /> }<br /> </span> </h3> <table cellpadding="1" cellspacing="0" border="0"> <tr> <td> <div class="div1">.div1{position:static;}</div> <div class="div2">.div2{position.static;}</div> </td> <td> <div class="div1" style=" z-index:2;">.div1{position:static; z-index:2;}</div> <div class="div2" style=" z-index:1;">.div2{position:static; z-index:1;}</div> </td> <td>结论:同为静态定位,html靠后者居上,并且如果有z-index也无效;当然,如果静态定位遇到动态定位,也肯定是要逊色而居下的。</td> </tr> <tr> <td> <div class="div1" style="position:relative;">.div1{position:relative}</div> <div class="div2" style="position:relative;">.div2{position:relative}</div> </td> <td> <div class="div1" style="position:relative; z-index:2">.div1{position:relative; z-index:2}</div> <div class="div2" style="position:relative; z-index:1">.div2{position:relative; z-index:1}</div> </td> <td>结论:同为动态relative定位时,如果没有z-index,则html靠后者居上,如果有z-index,则数值大者居上</td> </tr> <tr> <td> <div class="div1" style="position:absolute;">.div1{position.absolute}</div> <div class="div2" style="position:absolute;">.div2{position.absolute}</div> </td> <td> <div class="div1" style="position:absolute; z-index:2">.div1{position:absolute; z-index:2}</div> <div class="div2" style="position:absolute; z-index:1">.div2{position:absolute; z-index:1}</div> </td> <td>结论:同为动态absolute定位时,如果没有z-index,则html靠后者居上,如果有z-index,则数值大者居上</td> </tr> <tr> <td> <div class="div1" style="position:relative;">.div1{position.relative}</div> <div class="div2" style="position:absolute;">.div2{position.absolute}</div> </td> <td> <div class="div1" style="position:relative; z-index:2">.div1{position:relative; z-index:2}</div> <div class="div2" style="position:absolute; z-index:1">.div2{position:absolute; z-index:1}</div> </td> <td>结论:同为动态定位时,如果没有z-index,则html靠后者居上,如果有z-index,则数值大者居上</td> </tr> <tr> <td> <div class="div1" style="position:absolute; zoom:1;">.div1{position.absolute}</div> <div class="div2" style="position:relative; zoom:1;">.div2{position.relative}</div> </td> <td> <div class="div1" style="position:absolute; z-index:2; zoom:1;">.div1{position:absolute; z-index:2}</div> <div class="div2" style="position:relative; z-index:1; zoom:1;">.div2{position:relative; z-index:1}</div> </td> <td>结论:同为动态定位时,如果没有z-index,则html靠后者居上,如果有z-index,则数值大者居上</td> </tr> </table> </body> </html>