code: public static String getURI(Element elem) {
  		Attr attr = elem.getAttributeNodeNS(URI, SRC_ATTR);
  		return attr != null ? attr.getValue() : LocationUtils.UNKNOWN_STRING;
  	}
docs: Returns the URI of an element (DOM flavor)
  
  @param elem
  the element that holds the location information
  @return the element's URI or "<code>[unknown location]</code>" if
  <code>elem</code> has no location information.