XMLHttpRequest

var httpRequest;

if (window.XMLHttpRequest) {

	httpRequest = new XMLHttpRequest();

} else if (window.ActiveXObject) {

	httpRequest = new ActiveXObject("Microsoft.XMLHTTP");

}

<?xml version='1.0' encoding='utf-8'?>
<a>
	<b>b<b>
</a>

var a = httpRequest.responseXML.getElementsByTagName("a")[0];

var b = a.getElementsByTagName("b")[0].childNodes[0].nodeValue;

<?xml version='1.0' encoding='utf-8'?>
<a>
	<b><b>
</a>

b에 값이 없을 경우 에러나니 hasChildNodes()로 판단해줘도 됨

var b = "";

if (a.getElementsByTagName("a")[0].hasChildNodes()) {
	b = a.getElementsByTagName("a")[0].childNodes[0].nodeValue;
}

 

참고

http://www.tcpschool.com/ajax/ajax_server_xmlhttprequest

https://ggoreb.tistory.com/123