摘要： The web is constantly evolving. New and innovative websites are being created every day, pushing the boundaries of HTML in every direction. HTML 4 has been around for nearly a decade now, and publishers seeking new techniques to provide enhanced functionality are being held back by the constraints of the language and browsers. To give authors more flexibility and interoperability, and enable more interactive and exciting websites and applications, HTML 5 introduces and enhances a wi 阅读全文