code: public static String getTagAttr(StringBuilder page, final String tag,
  			final String attr) {
  
  		String found = null;
  		Pattern daPattern = TagMagix.getPattern(tag, attr);
  		Matcher matcher = daPattern.matcher(page);
  		int idx = 0;
  
  		if (matcher.find(idx)) {
  			found = matcher.group(1);
  			found = trimAttrValue(found);
  		}
  
  		return found;
  	}
docs: find and return the ATTR value within a TAG tag inside the HTML document
  within the StringBuffer page. returns null if no TAG-ATTR is found.
  
  @param page
  @param tag
  @param attr
  @return URL of base-href within page, or null if none is found.