DTD声明- ELEMENT 纯文本类型:(# PCDATA For example < ELEMENT year (#PCDATA)> valid <year>1999</year> <year>1999 CE</year> <year> The year of our Lord one thousand nine hundred, and ninety -nine </year> Invalid; <year> <month>January</month> <month>February</month> </year>DTD声明-ELEMENT „ 纯文本类型: (# ) PCDATA) „ For example: <!ELEMENT year (#PCDATA)> „ valid: <year>1999</year> <year>1999 C.E.</year> <year> The year of our Lord one thousand, nine hundred, and ninety-nine </year> „ Invalid: <year> < th>J </ th> <month>January</month> <month>February</month> </year>