first example jquery
Example 1: select the first elemnt have class in jquery
$( ".box" ).first().css( "font-style", "bold" );
Example 2: how to select the first div in jQuery
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>first demo</title>
<style>
td {
color: blue;
font-weight: bold;
}
</style>
<script src="https://code.jquery.com/jquery-3.5.0.js"></script>
</head>
<body>
<table>
<tr><td>Row 1</td></tr>
<tr><td>Row 2</td></tr>
<tr><td>Row 3</td></tr>
</table>
<script>
$( "tr:third" ).css( "font-style", "italic" );
</script>
</body>
</html>