<!DOCTYPE html>
<html>
<body>
<p id="demo"></p>
<script>
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
myFunction(this);
}
};
xhttp.open("GET", "books.xml", true);
xhttp.send();
function myFunction(xml) {
var x, i, xmlDoc, txt;
xmlDoc = xml.responseXML;
txt = "";
x = xmlDoc.getElementsByTagName('book');
for (i = 0; i < x.length; i++) {
x.item(i).setAttribute("category", "BESTSELLER");
}
for (i = 0; i < x.length; i++) {
txt += x[i].getAttribute('category') + "<br>";
}
document.getElementById("demo").innerHTML = txt;
}
</script>
</body>
</html>