JSFiddle - React, Tailwind, and code Playground

HTML

<div id="result1"></div>
<div id="result2"></div>

JavaScript

// Works in Chrome/FireFox and not in IE
$('#result1').html('text: ' + $('Entity', '<Entities><Entity Key="Customers"><ExtraData></ExtraData><MultipleMatches /></Entity></Entities>').map(function() {
    return $(this).attr('Key');
}).get());

// Works in IE Only
$('#result2').html('text: ' + $('<Entities><Entity Key="Customers"><ExtraData></ExtraData><MultipleMatches /></Entity></Entities>').closest('Entity').map(function() {
    return $(this).attr('Key');
}).get());