<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta http-equiv="X-UA-Compatible" content="ie=edge"> <title>小项目（冒泡事件的使用）</title> <style> *{margin: 0; padding: 0;} #div{ width: 100%; height: 400px; border: 1px solid black; } li{ width: 60px; height: 20px; border-radius: 10px/10px; text-align: center; float: left; margin-left: 5px; list-style: none; cursor: default; } #ul{margin: 0;} #ul>li:first-child{ background: red; } #ul>li:first-child+li{ background: green; } #ul>li:last-child{ background: blue; } </style> </head> <body> <div id="div"></div> <ul id="ul"> <li>红色</li> <li>绿色</li> <li>蓝色</li> </ul> <script> var div=document.getElementById("div");//获取div var ul=document.getElementById("ul");//获取ul //给ul绑定点击事件 ul.addEventListener("click",function(){ var li=event.target;//将事件源赋值给变量li //判断li的内容 if (li.innerHTML=="红色"){ div.style.background="red"; }else if (li.innerHTML=="绿色"){ div.style.background="green"; }else{ div.style.background="blue"; } }) </script> </body> </html>