<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<style>
*{list-style-type: none;}
#colcon li{ width: 50px; height: 50px; border:1px solid #ccc; float: left; margin:10px;line-height: 50px; background-color:#fcc;text-align: center;}
</style>
<script>
window.onload=function (){
var aUL=document.getElementById("colcon");
var aLI=aUL.getElementsByTagName("li");
aUL.onclick = function(ev){
var ev = ev || window.event;
var target = ev.target || ev.srcElement;
if(target.nodeName.toLowerCase == "li"){
var newcolo = target.innerHTML;
target.style.background = newcolo;
};
};
}
</script>
</head>
<body>
<ul id="colcon">
<li>#000</li>
<li>#ccc</li>
<li>#ddd</li>
</ul>
</body>
</html>
![[Web front-end] Permulaan pantas Node.js](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
toLowerCase后边加括号
这样就可以了，试着单步调试，用console.log()
target.nodeName.toLowerCase()
改成这个就可以了
楼上正解
toLowerCase(),你把后边的括号掉了。