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

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。

其他回答

这并不一定是一场战争。和谐是可能的。

使用一个表的整体布局和div在其中。

<table> 
    <tr><td colspan="3"><div>Top content</div></td></tr>
    <tr> 
        <td><div>Left navigation</div></td> 
        <td><div>Main content</div></td> 
        <td><div>Right navigation</div></td> 
    </tr>
    <tr><td colspan="3"><div>Bottom content</div></td></tr>
</table>

看,没有嵌套表。

我读过很多关于如何用divs实现这一点的文章,但从来没有发现任何事情,每次都没有问题。

一旦你有了整体结构,Divs是很棒的,但坦率地说,流体页眉/页脚和三个流体列是Divs的一大痛苦。Divs不是为流动性而设计的,所以为什么要使用它们呢?

注意,这种方法将在链接文本中提供100%的CSS遵从性

下面是来自最近项目的一段html:

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
    <title>{DYNAMIC(TITLE)}</title>
    <meta http-equiv="content-type" content="text/html;charset=utf-8" />
    <meta http-equiv="Content-Style-Type" content="text/css" />
    <link rel="stylesheet" type="text/css" href="./styles/base.css" />
</head>
<body>
    <div id="header">
        <h1><!-- Page title --></h1>
        <ol id="navigation">
            <!-- Navigation items -->
        </ol>
        <div class="clearfix"></div>
    </div>
    <div id="sidebar">
        <!-- Sidebar content -->
    </div>
    <!-- Page content -->
    <p id="footer"><!-- Footer content --></p>
</body>
</html>

这是与基于表格的布局相同的代码。

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
    <title>{DYNAMIC(TITLE)}</title>
    <meta http-equiv="content-type" content="text/html;charset=utf-8" />
    <meta http-equiv="Content-Style-Type" content="text/css" />
    <link rel="stylesheet" type="text/css" href="./styles/base.css" />
</head>
<body>
    <table cellspacing="0">
        <tr>
            <td><!-- Page Title --></td>
            <td>
                <table>
                    <tr>
                        <td>Navitem</td>
                        <td>Navitem</td>
                    </tr>
                </table>
            </td>
        </tr>
    </table>

    <table>
        <tr>
            <td><!-- Page content --></td>
            <td><!-- Sidebar content --></td>
        </tr>
        <tr>
            <td colspan="2">Footer</td>
        </tr>
    </table>
</body>
</html>

我在基于表格的布局中看到的唯一干净的地方是我对缩进的过度热情。我确信内容部分将有另外两个嵌入式表。

另一件需要考虑的事情是:文件大小。我发现基于表格的布局通常是CSS布局的两倍大。在我们的高速宽带上,这不是一个大问题,但在那些拨号调制解调器上。

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.

Flex有一个标签,用于在垂直列中布局内容。说实话,我不认为他们在布局/内容方面做得很好,但至少他们已经解决了这个问题。

像许多对CSS感到沮丧的人一样,我也到处寻找一个简单的答案,当我以为我找到了它时,我感到兴奋,然后当我在Chrome中打开页面时,我的希望破灭了。我肯定没有足够的技能说这是不可能的,但我还没有看到任何人提供样本代码供同行评审,明确地证明它可以可靠地完成。

那么,这个岛的CSS方面有人能推荐一种布局垂直列的心态/方法吗?我尝试过在第二行和第三行绝对定位,但我最终与到处重叠的东西和浮动有类似的问题,如果页面缩小。

如果这个问题有答案,我会欣喜若狂地做正确的事情——只要告诉我一些像“嘿,你试过**流:垂直|水平”这样的事情,我就完全不烦你了。

几年前,我研究了屏幕阅读器和表格的问题,得出了与大多数开发者想法相矛盾的信息:

http://www.webaim.org/techniques/tables/

你可能会听到一些易访问性倡导者说布局表是一个坏主意,应该使用CSS布局技术。他们说的有道理,但是,老实说,在可访问性方面,使用表格进行布局并不是最糟糕的事情。只要桌子在设计时考虑到可访问性,各种残疾的人都可以轻松地使用桌子。”