Returns a numeric code for the first character in a text string, in the character set used by your computer 返回字符串第一个字符在本机所用字符集中的数字代码
If missing characters are presented using their numeric representation, use the hexadecimal ( not decimal) form since this is the form used in character set standards. 如果缺失的字符用它们的数字编码来展现,要用字符集标准使用的十六进制而不是十进制来进行展现。