围绕语义标记的整个思想是标记和表示的分离，其中包括布局。

Div并没有取代表，它们在将内容分离为相关内容块(，)方面有自己的用途。当您不具备这些技能并且依赖于表格时，您通常必须将内容分离到单元格中以获得所需的布局，但是在使用语义标记时，您不需要触摸标记来实现表示。在生成标记而不是静态页面时，这一点非常重要。

开发人员需要停止提供暗示布局的标记，以便我们这些拥有显示内容技能的人能够继续工作，并且开发人员不必在表示需要更改时返回他们的代码进行更改。

WYSIWYG!!! I can't for the life of me get our designers to stop using nested DIVS and styled by elementID css in templates that are supposed to be used by clients in CMS projects. That's the whole point of a WYSIWYG online editor. You are controlling both the content and the layout at the same time! There is no separation at all in the first place in this scenario. Positioned and styled Divs in some external stylesheet are anathema to the whole idea of WYSIWYG editing. Tables can be seen, rows inserted, cells combined and so on. Good luck trying this with divs in a way that doesn't frustrate users.

看起来你只是习惯了桌子，仅此而已。 将布局放在表格中会限制你的布局。用CSS你可以移动位，看看http://csszengarden.com/ 不，布局通常不需要很多嵌套的div。

没有表格的布局和适当的语义HTML更干净，因此更容易阅读。 为什么不理解CSS的人要尝试阅读它呢?如果有人认为自己是web开发人员，那么对CSS的良好掌握是必须的。

SEO的好处来自于将最重要的内容放在页面上方的能力 拥有更好的内容与标记比率。

http://www.hotdesign.com/seybold/

当我使用CSS设计我的布局时，我通常给每个主要部分都有自己的根(主体级别)div，并使用相对/绝对定位将其置于适当的位置。这比表更灵活一些，因为我不局限于可以用行和列表示的排列。

此外，如果我决定我想要重新安排布局(说我想要导航栏现在在右边)，我可以简单地去改变一个地方(CSS文件)的元素位置，HTML不需要改变。如果我对表执行此操作，我将不得不进入并找到信息，并进行大量属性修改和复制粘贴以获得相同的效果。

事实上，使用CSS，我甚至可以让我的用户选择他们想要的布局如何工作。只要内容区域的一般大小不改变，我完全可以使用一些PHP脚本来根据用户的偏好输出CSS，并允许他们根据自己的喜好重新排列站点。同样，对于表也是可以的，但是维护起来要困难得多。

最后，CSS提供了一个表永远无法提供的主要好处:基于显示设备重新格式化内容的能力。CSS允许我在打印机上使用与显示器上完全不同的样式集(包括位置、格式等)。这也可以扩展到其他媒体，一个很好的例子是Opera Show，它允许一个设计巧妙(非常标准)的CSS增强页面被视为幻灯片显示。

因此，最终，灵活性和管理才是真正的赢家。一般来说，CSS允许你对布局做更多的事情。基于表的布局在技术上没有什么不标准的，但为什么要限制自己呢?

根据我对表的了解，如果嵌套了太多的表，在呈现页面时浏览器会有很大的开销。

1 -浏览器必须等待呈现最终视图，直到整个表被加载。

2 - The algorithm to render the table is expensive and is not in a single go. The browser, as and when, gets the contents, will try to render calculating the content width and height. So, if you are having nested tables, say, the browser has received the first row and the 1st cell is having large amount of content and width and height not defined, it will calculate the width and will render the first row, In the mean while it gets the 2nd row will cell#2 having loads of content! It will now calculate the width for 2nd row cells.. What about the first ? It will calculate widths recursively. That's bad at client side. (To site an example) As a programmer, you'll optimize stuffs such as time to fetch data, optimized data structures and etc. You optimize things to complete on server side, say in2 secs, but end user in getting the final view in 8 secs. What is wrong here ? 1. May be network is slow! What if network is fine ? What is network is delivering the contents in next 1 sec ? Where is this extra 5 secs getting consumed ? Thing to worry about-- The browser might be taking lot of time in estimating and rendering the tables!

如何优化表? 如果你使用表格，我建议，总是定义单元格的宽度。这并不能保证浏览器会盲目地只取这个宽度，但会对浏览器决定初始宽度有很大的帮助。

但是，最后，div是CSS可以被浏览器缓存的好方法;而表没有缓存!

Google gives very low priority to text content contained inside a table. I was giving some SEO advice to a local charity. In examining their website it was using tables to layout the site. Looking at each page, no matter what words - or combination of words - from their pages I used in the Google search box the pages would not come up in any of the top search pages. (However, by specifying the site in the search the page was returned.) One page was well copy written by normal standards to produce a good result in a search but still it didn't appear in any of the first pages of search results returned. (Note this text was within a table.) I then spotted a section of text on the pages which was in a div rather than a table. We put a few of the words from that div in the search engine. Result? It came in at No.2 in the search result.