func isValid(code string) bool {
	st := make([]string, 0)
	for i, r := range code {
		if 0 < i && len(st) == 0 {
			return false
		}
		if code[i:i+9] == "<![CDATA[" { // Parse cdata
			i = strings.Index(code[i+8:], "]]>")
			if i < 0 {
				return false
			}
			i += 2
		} else if code[i:i+2] == "</" {
			name := 
		} else if r == '<' {
			
		}
	}
	return len(st) == 0
}