<!DOCTYPE html>
<html lang="en-US">
<body>
<p data-id="1245" data-user="johnsmith" data-age="35">John Smith</p>
<button onclick="myFunction()">Read All Attribute</button>
<p id="point"></p>
<script>
var x = document.getElementById("point");
var elem = document.getElementsByTagName("p")[0];
var txt = "";
// Add John's weight;
elem.dataset.weight = "50 kg";
function myFunction(){
var len = elem.attributes.length;
for(var i=0; i<len; i++)
txt += elem.attributes[i].name +" = "+ elem.attributes[i].value +"<br>";
x.innerHTML = txt;
}
</script> </body>
</html>