????：<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xml
<!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>無標(biāo)題文檔</title>
</head>
<body>
<ul id="ul">
<li class="today">今天</li>
<li class="tommorrow">明天</li>
<li class="houtian">后天</li>
<li class="dahoutian">大后天</li>
</ul>
<script type="text/javascript">
let lists = document.querySelectorAll("li");
lists[0].style.backgroundColor="red";
lists[1].style.backgroundColor="blue";
//console.log(lists)
let ul = document.querySelector("#ul");//返回滿足條件的第一個
console.log(ul);
let li = ul.querySelectorAll(".houtian");
li[0].style.backgroundColor="yellow";
</script>
</body>
</html>
?? ???：查無此人?? ??：2019-04-23 13:39:51
???? ??：完成的不錯。js是終身學(xué)習(xí)的語言，要好好學(xué)習(xí)。繼續(xù)加油