Sample Servicenow script showing how to handle case of non existing XML tag.

servicenow_getNode.js

/*
 * Checks if given node indeed of given tag.
 * Params:
 *  tag - String, name of tag to check
 *  node - XMLNode, node in which to check for the tag
 * Returns:
 *  true, if tag is present
 *  false, otherwise
 */
function isNodeOfTag (node, tag) {
  try {
    if (tag == node.getNodeName()) {
      gs.info("Given node indeed belongs to tag " + tag);
      return true;
    }
  } catch (error) {
    gs.error("Given node might not belong to tag " + tag + ". Error while checking: " + error);
    return false;
  }
}

var xmlString = "<test>" +
                "  <one>" +
                "    <two att=\"xxx\">abcd1234</two>" +
                "    <three boo=\"yah\" att=\"yyy\">1234abcd</three>" +
                "    <two>another</two>" +
                "  </one>" +
                "  <number>1234</number>" +
                "</test>";

var xmlDoc = new XMLDocument2();
xmlDoc.parseXML(xmlString);

var node = xmlDoc.getNode("/test/one/two"); // tag 'two' is present in this XML.
isNodeOfTag(node, "two");

var node = xmlDoc.getNode("/test/one/four"); // tag 'four' is not present in this XML.
isNodeOfTag(node, "four");

servicenow_getNode_output.txt

Given node indeed belongs to tag two
Given node might not belong to tag four. Error while checking: java.lang.NullPointerException