由于缺少结构，即使是形式良好的 HTML 页面也比较难以处理。必须分析标题的级别，才能看出各个部分的划分方式。边栏、页脚、页眉、导航条、主内容区和各篇文章都由通用的 div 元素来表示。HTML 5 添加了一些新元素，专门用来标识这些常见的结构：
· section：这可以是书中的一章或一节，实际上可以是在 HTML 4 中有自己的标题的任何东西
· header：页面上显示的页眉；与 head 元素不一样
· footer：页脚；可以显示电子邮件中的签名
· nav：指向其他页面的一组链接
· article：blog、杂志、文章汇编等中的一篇文章
我们来考虑一个典型的 blog 主页，它的顶部有页眉，底部有页脚，还有几篇文章、一个导航区和一个边栏，见代码1 典型的 blog 页面
"/blog/birding/2007/04/23/spring-comes-and-goes-in-sussex-county/">
Spring Comes (and Goes) in Sussex County
yesterday i joined the brooklyn bird club for our
annual trip to western new jersey, specifically hyper
humus, a relatively recently discovered hot spot. it
started out as a nice winter morning when we arrived
at the site at 7:30 a.m., progressed to spring around
10:00 a.m., and reached early summer by 10:15.
"/blog/birding/2007/04/23/but-does-it-count-for-your-life-list/">
But does it count for your life list?
Seems you can now go href="http://www.wired.com/science/discoveries/news/
2007/04/cone_sf">bird watching via the Internet. I
haven't been able to test it out yet (20 user
limit apparently) but this is certainly cool.
Personally, I can't imagine it replacing
actually being out in the field by any small amount.
On the other hand, I've always found it quite
sad to meet senior birders who are no longer able to
hold binoculars steady or get to the park. I can
imagine this might be of some interest to them. At
least one elderly birder did a big year on TV, after
he could no longer get out so much. This certainly
tops that.
立即学习“前端免费学习笔记（深入）”；
即使有正确的缩进，这些嵌套的 div 仍然让人觉得非常混乱。在 HTML 5 中，可以将这些元素替换为语义性的元素，见代码2 用 HTML5编写的典型blog页面
Mokka mit Schlag
"/blog/birding/2007/04/23/spring-comes-and-goes-in-sussex-county/">
Spring Comes (and Goes) in Sussex County
Yesterday I joined the Brooklyn Bird Club for our
annual trip to Western New Jersey, specifically Hyper
Humus, a relatively recently discovered hot spot. It
started out as a nice winter morning when we arrived at
the site at 7:30 A.M., progressed to Spring around 10:00
A.M., and reached early summer by 10:15.
Python v2.4版chm格式的中文手册，内容丰富全面，不但是一本手册，你完全可以把她作为一本Python的入门教程，教你如何使用Python解释器、流程控制、数据结构、模板、输入和输出、错误和异常、类和标准库详解等方面的知识技巧。同时后附的手册可以方便你的查询。
"/blog/birding/2007/04/23/but-does-it-count-for-your-life-list/">
But does it count for your life list?
Seems you can now go href="http://www.wired.com/science/discoveries/news/
2007/04/cone_sf">bird watching via the Internet. I
haven't been able to test it out yet (20 user
limit apparently) but this is certainly cool.
Personally, I can't imagine it replacing
actually being out in the field by any small amount.
On the other hand, I've always found it quite
sad to meet senior birders who are no longer able to
hold binoculars steady or get to the park. I can
imagine this might be of some interest to them. At
least one elderly birder did a big year on TV, after
he could no longer get out so much. This certainly
tops that.
立即学习“前端免费学习笔记（深入）”；
现在不再需要 div 了。不再需要自己设置 class 属性，从标准的元素名就可以推断出各个部分的意义。这对于音频浏览器、手机浏览器和其他非标准浏览器尤其重要。
（待续）
