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

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.

其他回答

我尽量避免使用TABLEs,但是当我们设计复杂的表单,混合了多种控件类型和不同的标题位置,并对分组进行了非常严格的控制时,使用DIVs是不可靠的,甚至几乎是不可能的。

现在,我不会说这些表单不能重新设计以更好地适应基于DIV的布局,但是对于其中的一些表单,我们的客户坚决不改变以前版本(用经典ASP编写的)的现有布局,因为它与用户熟悉的纸质表单相似。

因为表单的表示是动态的(其中某些部分的显示是基于案例的状态或用户的权限),所以我们使用一组堆叠的div,每个div包含一个由逻辑分组的表单元素组成的TABLE。TABLE的每一列都被分类,这样CSS就可以控制它们。这样,我们就可以关闭表单的不同部分,而不会出现在div中不是表来换行的问题。

我曾经了解到,一个表是立即加载的,换句话说,当连接很慢的时候,表所在的空间保持空白,直到整个表被加载,另一方面,一个div加载从上到下的速度与数据到达的速度一样快,不管它是否已经完成。

我想补充的是,基于div的布局更容易维护、发展和重构。只是在CSS中做了一些改变来重新排序元素,这就完成了。根据我的经验,重新设计使用表的布局是一场噩梦(如果有嵌套的表,则会更糟)。

从语义的角度来看,代码也有意义。

无论如何,这并不是一个明确的论点,但是对于CSS,你可以使用相同的标记并根据介质改变布局,这是一个很好的优势。例如,对于打印页面,您可以安静地抑制导航,而不必创建打印机友好的页面。

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。