<!DOCTYPE html> <html lang="ja"> <head> <meta charset="utf-8"> <title>Hello!</title> </head> <body> <h1 id="someID">はろーわーるど</h1> <p >クリックしてね</p> <script type="text/javascript" charset="utf-8"> document.getElementById("someID").addEventListener("click", (ev) => { alert("Hello"); }); </script> </body> </html>