「jQuery」セレクタにeq()を使うサンプル
書式
$(“p:eq(インデックス番号)")
$(“#id名")
$(“.クラス名")
使用例
<!DOCTYPE html>
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<script>
$(document).ready(function(){
$("p:eq(1)").css("background-color","yellow");
$("#KB").css("background-color","green");
$(".intro").css("background-color","red");
});
</script>
</head>
<body>
<p class="intro">test data 01.</p>
<p>test data 02.</p>
<p>test data 03.</p>
<p>222:</p>
<ul id="choose">
<li>demo01</li>
<li id="KB">demo02</li>
<li>demo03</li>
</ul>
</body>
</html>
<!DOCTYPE html>
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<script>
$(document).ready(function(){
$("p:eq(1)").css("background-color","yellow");
$("#KB").css("background-color","green");
$(".intro").css("background-color","red");
});
</script>
</head>
<body>
<p class="intro">test data 01.</p>
<p>test data 02.</p>
<p>test data 03.</p>
<p>222:</p>
<ul id="choose">
<li>demo01</li>
<li id="KB">demo02</li>
<li>demo03</li>
</ul>
</body>
</html>
<!DOCTYPE html>
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
<script>
$(document).ready(function(){
$("p:eq(1)").css("background-color","yellow");
$("#KB").css("background-color","green");
$(".intro").css("background-color","red");
});
</script>
</head>
<body>
<p class="intro">test data 01.</p>
<p>test data 02.</p>
<p>test data 03.</p>
<p>222:</p>
<ul id="choose">
<li>demo01</li>
<li id="KB">demo02</li>
<li>demo03</li>
</ul>
</body>
</html>