Xpath - select either or

HTML

<div>

  <p>a</p>

</div>

<div>

  <select>b</select>

</div>

JavaScript

//https://developer.mozilla.org/en/docs/Web/API/Document/evaluate
/*var els = document.evaluate('/html/body//div[@id="root1"]//input | //select', document, null, XPathResult.ANY_TYPE, null); 
var el = els.iterateNext(); 
console.log(el.tagName);

var els = document.evaluate('/html/body//div[@id="root2"]//input | //select', document, null, XPathResult.ANY_TYPE, null); 
var el = els.iterateNext(); 
console.log(el.tagName);

var els = document.evaluate('/html/body//div[@id="root1"]//*[self::input or self::select]', document, null, XPathResult.ANY_TYPE, null); 
var el = els.iterateNext(); 
console.log(el.tagName);

var els = document.evaluate('/html/body//div[@id="root2"]//*[self::input or self::select]', document, null, XPathResult.ANY_TYPE, null); 
var el = els.iterateNext(); 
console.log(el.tagName);
*/
var els = document.evaluate('/html/body/div/*[self::p or self::select]', document, null, XPathResult.ANY_TYPE, null); 
var el = els.iterateNext(); 
console.log(el.tagName);
var el = els.iterateNext(); 
console.log(el.tagName);