code: private synchronized static Pattern getAttrPattern(String attrName) {
  
  		Pattern pc = attrPatterns.get(attrName);
  		if (pc == null) {
  
  			String attrPatString = "\\b" + attrName + "\\s*=\\s*("
  					+ ANY_ATTR_VALUE + ")(?:\\s|>)?";
  
  			pc = Pattern.compile(attrPatString, Pattern.CASE_INSENSITIVE);
  			attrPatterns.put(attrName, pc);
  		}
  		return pc;
  	}
docs: get (and cache) a regex Pattern for locating an attribute value within an
  HTML start tag. If this pattern matches, the attribute value will be in
  group(1), and will include surrounding quotes, or apos, if they were
  present in the original HTML.
  
  @param attrName
  @return Pattern to match the attributes value