什么名字都被占用
<!DOCTYPE html><html> <head> <meta charset="UTF-8" /> <title>Document</title> <style> /*子元素偏移是相对于父层.wrap来定位*/ #trip1{ width: 0px; height: 0px; border-top: 50px solid rgba(200,200,200,0); border-right: 50px solid rgba(200,200,200,0); border-bottom: 50px solid green; border-left: 50px solid rgba(200,200,200,0);position: absolute;top: 0;left: 50%;margin-left: -50px; } #trip2{ width: 0px; height: 0px; border-top: 100px solid rgba(200,200,200,0); border-right: 100px solid rgba(200,200,200,0); border-bottom: 100px solid green; border-left: 100px solid rgba(200,200,200,0); position: absolute;top:0px;left: 50%;margin-left: -100px;} /*设置父元素相对定位*/ .wrap{width: 500px;height:300px;margin: 20px auto;position: relative;} </style> </head> <body> <div class="wrap"> <div id="trip1"></div> <div id="trip2"></div> </div> </body></html>