public boolean validate(String s) {
		if (s == null)
			throw new NullPointerException("validate: null input");
		failedTag = null;
		Matcher m = patt.matcher(s);
		while (m.find()) {
				String tagName = m.group(1);
				System.out.println(tagName);
				// If even one tag bad, we return false.
				if (!okTag(tagName)) {
					failedTag = tagName;
					return false;
				}
		}
		// No bad tags found...
		return true;
	}