JSFiddle - React, Tailwind, and code Playground

JavaScript

validateXML('<?xml version="1.0" ?><!DOCTYPE anything SYSTEM "$target$">')
/////////////////////////////////////////////////////////////////////////////////
function validateXML(txt) {
    // code for IE
    if (window.ActiveXObject) {
        var xmlDoc = new ActiveXObject("Microsoft.XMLDOM");
        xmlDoc.async = true;
        try {
            xmlDoc.loadXML(txt);
			if (xmlDoc.parseError.errorCode != 0) {
				var err;
				err = "Error Code: " + xmlDoc.parseError.errorCode + "\n";
				err += "Error Reason: " + xmlDoc.parseError.reason;
				err += "Error Line: " + xmlDoc.parseError.line;
				alert(err);
				var errReason = xmlDoc.parseError.reason.toLowerCase();
				alert(errReason);
			} else {
                alert('No Error? Unknown!')
			}
        } catch (e) {
            alert(e);           
        }
		
        
    } else {
        alert('you need to use IE')
    }
}