<!DOCTYPE html>
<html lang="en-US">
<body>
<p data-id="1245" data-user="johnsmith" data-age="35">John Smith</p>
<button onclick="myFunction()">Display User Id</button>
<p id="point"></p>
<script>
var x = document.getElementById("point");
var elem = document.getElementsByTagName("p")[0];
var txt = "";
function myFunction(){
x.innerHTML = elem.dataset.id;
}
</script> </body>
</html>