JSFiddle - React, Tailwind, and code Playground

HTML

<input id="test:1" value=test1 />

JavaScript

var str = "<?xml version='1.0' encoding='utf-8'?><xsl:stylesheet version='1.0' xmlns:xsl='http://www.w3.org/1999/XSL/Transform'><xsl:output method='text' encoding='utf-8' /><xsl:variable name='title'>aaa</xsl:variable><xsl:variable name='col1'>CSV00001</xsl:variable><xsl_variable name='test'>test</xsl_variable></xsl:stylesheet>";

function StringtoXML(text){
                if (window.ActiveXObject){
                  var doc=new ActiveXObject('Microsoft.XMLDOM');
                  doc.async='false';
                  doc.loadXML(text);
                } else {
                  var parser=new DOMParser();
                  var doc=parser.parseFromString(text,'text/xml');
                }
                return doc;
}

var csvXsl = StringtoXML(str);

alert("input tag works -- " + $("#test\\:1").val());

alert("this works, too -- " + $(csvXsl).find("xsl_variable")[0]);

alert("But when I try to escape the colon to access the xsl:variable tag, it comes up as undefined...");

var nodes = $(csvXsl).find("xsl\\:variable")[0];

alert(nodes);