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。


当前回答

内容和布局之间的分离也使它更容易为您的网站生成打印机友好的布局或不同的皮肤(样式),而不必创建不同的html文件。有些浏览器(如Firefox)甚至支持从视图菜单中选择样式表。

而且我确实认为保持无表格布局更容易。你不需要担心行span, colspan等等。您只需创建一些容器div并将内容放置在需要的位置。也就是说,我认为它也更有可读性(<div id="sidebar"> vs <tr><td>…</td><td>…<td>sidebar</td></tr>)。

这只是一个你必须学会的小“技巧”(一旦你掌握了这个技巧,我认为它会更容易,更有意义)。

其他回答

In the past, screen readers and other accessibility software had a difficult time handling tables in an efficient fashion. To some extent, this became handled in screen readers by the reader switching between a "table" mode and a "layout" mode based on what it saw inside the table. This was often wrong, and so the users had to manually switch the mode when navigating through tables. In any case, the large, often highly nested tables were, and to a large extent, are still very difficult to navigate through using a screen reader.

The same is true when divs or other block-level elements are used to recreate tables and are highly nested. The purpose of divs is to be used as a fomating and layout element, and as such, are intended used to hold similar information, and lay it out on the screen for visual users. When a screen reader encounters a page, it often ignores any layout information, both CSS based, as well as html attribute based(This isn't true for all screen readers, but for the most popular ones, like JAWS, Windows Eyes, and Orca for Linux it is).

为此,表格式数据,也就是逻辑上有意义的在二维或多维维度中排序的数据,具有某种标题,最好放在表中,并使用div来管理页面上内容的布局。(另一种思考“表格数据”的方式是尝试以图表形式绘制它……如果你不能,它可能不是最好的表示在一个表中)

Finally, with a table-based layout, in order to achieve a fine-grained control of the position of elements on the page, highly nested tables are often used. This has two effects: 1.) Increased code size for each page - Since navigation and common structure is often done with the tables, the same code is sent over the network for each request, whereas a div/css based layout pulls the css file over once, and then uses less wordy divs. 2.) Highly nested tables take much longer for the client's browser to render, leading to slightly slower load times.

在这两种情况下,“最后一英里”带宽的增加,以及更快的个人电脑缓解了这些因素,但它们仍然是许多网站存在的问题。

With all of this in mind, as others have said, tables are easier, because they are more grid-oriented, allowing for less thought. If the site in question is not expected to be around long, or will not be maintained, it might make sense to do what is easiest, because it might be the most cost effective. However, if the anticipated userbase might include a substantial portion of handicapped individuals, or if the site will be maintained by others for a long time, spending the time up front to do things in a concise, accessible way may payoff more in the end.

在维护内容的同时进行网站维护和设计检修(这一直都在发生,尤其是在电子商务中):

内容和设计通过表格混合在一起=更新内容和设计。

内容与设计分离=更新设计和少量内容。

如果我有自己的方式,我会将内容保存在PHP中,生成XML,转换为XSLT中的标记,并使用CSS和Javascript进行交互设计。对于Java方面的东西,JSP到JSTL来生成标记。

使用表格布局的工具可能会因为创建布局所需的大量代码而变得异常沉重。SAP的Netweaver Portal默认使用TABLE来布局页面。

在我目前的工作中,生产SAP门户有一个主页,它的HTML超过60K,有7个表那么深,在页面中有3次。再加上Javascript,误用了16个iframe,其中有类似的表格问题,CSS过重等,页面重量超过5MB。

花点时间降低页面重量,这样你就可以利用带宽与用户进行互动,这是值得的。

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。

下面是我的程序员在一个类似的帖子中给出的答案

语义101

首先看一下这段代码,想想哪里出了问题……

class car {
    int wheels = 4;
    string engine;
}

car mybike = new car();
mybike.wheels = 2;
mybike.engine = null;

当然,问题在于自行车不是汽车。car类对于bike实例是不合适的类。代码没有错误,但是语义不正确。这对程序员的形象很不利。

语义102

现在将此应用于文档标记。如果您的文档需要显示表格数据,那么适当的标记将是<table>。但是,如果将导航放在表中,则滥用了<table>元素的预期用途。在第二种情况下,您没有表示表格数据—您(mis)使用<table>元素来实现表示目标。

结论

游客会注意到吗?不。你的老板在乎吗?也许吧。作为程序员,我们有时会偷工减料吗?当然。但是我们应该吗?不。如果使用语义标记,谁会受益?你,还有你的职业声誉。现在去做正确的事吧。