想像一下我们从WWW上获取信息时,计算机同Internet打交道所使用的语言吧,或许你能够看出计算机之间在使用四种不同的语言进行交谈。其中有三种十分简洁而严格,它们仅仅被计算机所理解和使用,而正是第四种HTML语言创造了当今神奇的网络现象。HTML语言和英语很相像,人们已经开始学着用它来编写文档。这样几乎在所有计算机上你都能够显示它们。但是HTML仍然是太严格了,对其有限“词汇”的每一次扩展,都必须经过一个专门 Imagine the language that computers use to deal with the Internet when getting information from the WWW. Perhaps you can see that computers are talking in four different languages. Three of them are very concise and rigorous, they are only understood and used by computers, and it is the fourth HTML language that creates the magic of today’s web. HTML language and English are very similar, people have begun to learn to use it to write documents. So you can show them on almost any computer. But HTML is still too strict, and every extension of its limited “vocabulary” must go through a specialized