简化的声明 HTML 5 <!DOCTYPE HTML> <html> <head> <title>Title of the document</title> </head> <body> The content of the document. . . </body> </html> HTML 4有三种声明:Strict、 Transitional 以及 Frameset <!DOCTYPE HTML PUBLIC "-//W 3 C//DTD HTML 4. 01//EN" " http: //www. w 3. org/TR/htm l 4/strict. dtd"> <html> … … </html>