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。
一个例子:你想要居中
一个页面的主要内容区域,但在
为了把浮体装在里面,
它需要浮动。没有
CSS中的float: center。
这并不是在居中元素中“包含浮点数”的唯一方法。所以,这根本不是一个好的论点!
在某种程度上,“divs vs table”是一个错误的前提。
把一页快速地分成三列?说实话,表格更简单。但是没有专业人士将它们用于布局,因为它们将页面元素的位置锁定在页面中。
真正的争论是“由CSS完成的定位(最好是在远程文件中)”,而不是“在页面中由HTML完成的定位”。相对于后者,每个人都能看到前者的好处吗?
Size -- if your page layout is in the HTML, in the pages, it can't be cached, and it has to be repeated on every page. You will save enormous amounts of bandwidth if your layout is in a cached CSS file, not in the page.
Multiple developers can work on the same page at the same time -- I work on the HTML, other guy works on the CSS. No repository needed, no problems with over-writing, file locking etc.
Making changes is easier -- there will be problems with layout in different browsers, but you only have to fix one file, the CSS file, to sort them out.
Accessibility, as mentioned a lot previously. Tables assume a two-dimensional layout works for everyone. That's not how some users view your content and it's not how Google views your content.
考虑一下:
[ picture ] [ picture ] [ picture ]
[ caption ] [ caption ] [ caption ]
表示包含6个单元格的表中的两行。能看到二维表格布局的人会在每张图片下看到标题。但是使用语音合成,或者PDA,以及搜索引擎蜘蛛,那是
picture picture picture caption caption caption
有了表格,这种关系就明显消失了。
div和CSS是否更适合在HTML页面上简单地布局矩形以在最短的时间内实现给定的设计?不,他们可能不是。但我不是在快速布局矩形来实现给定的设计。我想的是更大的前景。
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。
使用DIV,您可以轻松地进行切换。例如,你可以这样做:
Menu | Content
Content | Menu
Menu
----
Content
在CSS中更改它很容易,而在HTML中则不然。你也可以提供几种风格(右手,左手,专为小屏幕)。
在CSS中,您还可以将菜单隐藏在用于打印的特殊样式表中。
另一个好处是,你的内容在代码中总是按照相同的顺序(菜单在前,内容在后),即使在视觉上它是以其他方式呈现的。