點(diǎn)評(píng)： 由于缺少結(jié)構(gòu)，即使是形式良好的 HTML 頁面也比較難以處理。必須分析標(biāo)題的級(jí)別，才能看出各個(gè)部分的劃分方式。邊欄、頁腳、頁眉、導(dǎo)航條、主內(nèi)容區(qū)和各篇文章都由通用的 div 元素來表示。HTML 5 添加了一些新元素，專門用來標(biāo)識(shí)這些常見的結(jié)構(gòu)：
· sectio
由于缺少結(jié)構(gòu)，即使是形式良好的 HTML 頁面也比較難以處理。必須分析標(biāo)題的級(jí)別，才能看出各個(gè)部分的劃分方式。邊欄、頁腳、頁眉、導(dǎo)航條、主內(nèi)容區(qū)和各篇文章都由通用的 div 元素來表示。HTML 5 添加了一些新元素，專門用來標(biāo)識(shí)這些常見的結(jié)構(gòu)：
· section：這可以是書中的一章或一節(jié)，實(shí)際上可以是在 HTML 4 中有自己的標(biāo)題的任何東西
· header：頁面上顯示的頁眉；與 head 元素不一樣
· footer：頁腳；可以顯示電子郵件中的簽名
· nav：指向其他頁面的一組鏈接
· article：blog、雜志、文章匯編等中的一篇文章
我們來考慮一個(gè)典型的 blog 主頁，它的頂部有頁眉，底部有頁腳，還有幾篇文章、一個(gè)導(dǎo)航區(qū)和一個(gè)邊欄，見代碼1 典型的 blog 頁面
<html>
<head>
<title>Mokka mit Schlag </title>
</head>
<body>
<div id="page">
<div id="header">
<h1><a href="http://www.elharo.com/blog">Mokka mit Schlag</a></h1>
</div>
<div id="container">
<div id="center" class="column">
<div class="post" id="post-1000572">
<h2><a href=
"/blog/birding/2007/04/23/spring-comes-and-goes-in-sussex-county/">
Spring Comes (and Goes) in Sussex County</a></h2>
<div class="entry">
<p>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. </p>
</div>
</div>
<div class="post" id="post-1000571">
<h2><a href=
"/blog/birding/2007/04/23/but-does-it-count-for-your-life-list/">
But does it count for your life list?</a></h2>
<div class="entry">
<p>Seems you can now go <a
href="http://www.wired.com/science/discoveries/news/
2007/04/cone_sf">bird watching via the Internet</a>. 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.</p>
</div>
</div>
</div>
<div class="navigation">
<div class="alignleft">
<a href="/blog/page/2/">« _fcksavedurl=""/blog/page/2/">«" Previous Entries</a>
</div>
<div class="alignright"></div>
</div>
</div>
<div id="right" class="column">
<ul id="sidebar">
<li><h2>Info</h2>
<ul>
<li><a href="/blog/comment-policy/">Comment Policy</a></li>
<li><a href="/blog/todo-list/">Todo List</a></li>
</ul></li>
<li><h2>Archives</h2>
<ul>
<li><a href='/blog/2007/04/'>April 2007</a></li>
<li><a href='/blog/2007/03/'>March 2007</a></li>
<li><a href='/blog/2007/02/'>February 2007</a></li>
<li><a href='/blog/2007/01/'>January 2007</a></li>
</ul>
</li>
</ul>
</div>
<div id="footer">
<p>Copyright 2007 Elliotte Rusty Harold</p>
</div>
</div>
</body>
</html>
即使有正確的縮進(jìn)，這些嵌套的 div 仍然讓人覺得非常混亂。在 HTML 5 中，可以將這些元素替換為語義性的元素，見代碼2 用 HTML5編寫的典型blog頁面
<html>
<head>
<title>Mokka mit Schlag </title>
</head>
<body>
<header>
<h1><a href="http://www.elharo.com/blog">Mokka mit Schlag</a></h1>
</header>
<section>
<article>
<h2><a href=
"/blog/birding/2007/04/23/spring-comes-and-goes-in-sussex-county/">
Spring Comes (and Goes) in Sussex County</a></h2>
<p>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. </p>
</article>
<article>
<h2><a href=
"/blog/birding/2007/04/23/but-does-it-count-for-your-life-list/">
But does it count for your life list?</a></h2>
<p>Seems you can now go <a
href="http://www.wired.com/science/discoveries/news/
2007/04/cone_sf">bird watching via the Internet</a>. 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.</p>
</article>
<nav>
<a href="/blog/page/2/">« _fcksavedurl=""/blog/page/2/">«" Previous Entries</a>
</nav>
</section>
<nav>
<ul>
<li><h2>Info</h2>
<ul>
<li><a href="/blog/comment-policy/">Comment Policy</a></li>
<li><a href="/blog/todo-list/">Todo List</a></li>
</ul></li>
<li><h2>Archives</h2>
<ul>
<li><a href='/blog/2007/04/'>April 2007</a></li>
<li><a href='/blog/2007/03/'>March 2007</a></li>
<li><a href='/blog/2007/02/'>February 2007</a></li>
<li><a href='/blog/2007/01/'>January 2007</a></li>
</ul>
</li>
</ul>
</nav>
<footer>
<p>Copyright 2007 Elliotte Rusty Harold</p>
</footer>
</body>
</html>
現(xiàn)在不再需要 div 了。不再需要自己設(shè)置 class 屬性，從標(biāo)準(zhǔn)的元素名就可以推斷出各個(gè)部分的意義。這對(duì)于音頻瀏覽器、手機(jī)瀏覽器和其他非標(biāo)準(zhǔn)瀏覽器尤其重要。
（待續(xù)）