<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <title>jQuery Select Element by Class</title> <script src="https://code.jquery.com/jquery-3.5.1.min.js"></script> <script> $(document).ready(function(){ // Highlight elements with class mark $(".mark").css("background", "blue"); }); </script> </head> <body> <p>Selecting Elements by ID.</p> <p class="mark">A paragraph</p> <p class="mark">A another paragraph</p> <p>A one more paragraph</p> </body> </html>