revision:
setAttributeNodeNS() method adds a new namespaced attribute node to an element.
setAttributeNodeNS(attributeNode)
Parameters:
attributeNode : an Attr node.
// <div id="one" xmlns:myNS="http://www.mozilla.org/ns/specialspace"
// myNS:special-align="utterleft">one</div>
// <div id="two">two</div>
const myns = "http://www.mozilla.org/ns/specialspace";
const d1 = document.getElementById("one");
const d2 = document.getElementById("two");
const a = d1.getAttributeNodeNS(myns, "special-align");
d2.setAttributeNodeNS(a.cloneNode(true));
alert(d2.attributes[1].value); // returns: `utterleft'