}

// asciiAlphaNum reports whether c is an ASCII letter or digit.
func asciiAlphaNum(c byte) bool {
	return asciiAlpha(c) || '0' <= c && c <= '9'
}

// eatTagName returns the largest j such that s[i:j] is a tag name and the tag type.
func eatTagName(s []byte, i int) (int, element) {
	if i == len(s) || !asciiAlpha(s[i]) {
		return i, elementNone
	}
	j := i + 1
	for j < len(s) {
		x := s[j]