在HTML中,表格不应该用于布局,这似乎是普遍的观点。
Why?
我从来没有(老实说,很少)看到过支持这一点的有力论据。通常的答案是:
It's good to separate content from layoutBut this is a fallacious argument; Cliche Thinking. I guess it's true that using the table element for layout has little to do with tabular data. So what? Does my boss care? Do my users care?Perhaps me or my fellow developers who have to maintain a web page care... Is a table less maintainable? I think using a table is easier than using divs and CSS.By the way... why is using a div or a span good separation of content from layout and a table not? Getting a good layout with only divs often requires a lot of nested divs.
Readability of the codeI think it's the other way around. Most people understand HTML, few understand CSS.
It's better for SEO not to use tablesWhy? Can anybody show some evidence that it is? Or a statement from Google that tables are discouraged from an SEO perspective?
Tables are slower.An extra tbody element has to be inserted. This is peanuts for modern web browsers. Show me some benchmarks where the use of a table significantly slows down a page.
A layout overhaul is easier without tables, see css Zen Garden.Most web sites that need an upgrade need new content (HTML) as well. Scenarios where a new version of a web site only needs a new CSS file are not very likely. Zen Garden is a nice web site, but a bit theoretical. Not to mention its misuse of CSS.
我对使用divs + CSS而不是表的良好参数非常感兴趣。
The issue of strictly separating presentation and content strikes me as roughly analogous to separating header files from implementation files in C++. It makes sense, but it can also be a pain. Witness Java and C# where classes are defined in a single source file. The authors of the newer languages noticed something that was causing programmers headaches and they got rid of it. That seems to be the gist of this discussion. One side is saying CSS is too difficult, the other side is saying one must become a CSS master.
对于简单的布局问题,为什么不改变表示必须完全独立的规则呢?一个新的标签(或者一些div标签的扩展)可以让我们直接在HTML中控制显示?毕竟,我们不是已经将表示泄露到HTML中了吗?看看h1, h2, h6。我们都知道这些控制表示。
阅读代码(HTML就是代码)的能力非常重要。专家们往往忽略了使编程环境尽可能为大众所接受的重要性。认为只有专业程序员才重要是非常短视的。
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!
我很抱歉我的英语不好,但还有一个原因:
我在一些政府机构工作,不使用TABLE的首要原因是残疾人。他们使用机器“翻译”网页。
问题是这个“翻译机器”不能阅读网站,如果它是由TABLE。为什么?因为TABLE是用于数据的。
事实上,如果你使用TABLES,你必须为每个cell指定一些信息,让残疾人知道他们在TABLE中的位置。想象一下,你有一个大表格,必须放大才能看到屏幕上的一个单元格:你必须知道你在哪一行/col。
因此,使用DIV,并且禁用可以简单地阅读文本,并且不会得到一些关于行/cols的奇怪信息,当它们不需要在那里时。
我也更喜欢TABLE来制作快速简单的模板,但我现在习惯了CSS…它很强大,但你真的必须知道你在做什么……:)