Should I make HTML Anchors with 'name' or

2018-12-31 04:05发布

When one wants to refer to some part of a webpage with the "http://example.com/#foo" method, should one use

<h1><a name="foo"/>Foo Title</h1>

or

<h1 id="foo">Foo Title</h1>

They both work, but are they equal, or do they have semantic differences?

14条回答
残风、尘缘若梦
2楼-- · 2018-12-31 04:20

Heads up for JavaScript users: all IDs become global variables under window.

<h1 id="foo">Foo Title</h1>

Just created the JS global:

window.foo

The value of window.foo will be the HTMLElement for the h1.

Unless you can guarantee all values used in id attributes are safe, you may prefer sticking to name:

<h1 name="foo">Foo Title</h1>
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孤独总比滥情好
3楼-- · 2018-12-31 04:21

Just an observation about the markup The markup form in prior versions of HTML provided an anchor point. The markup forms in HTML5 using the id attribute, while mostly equivalent, require an element to identify, almost all of which are normally expected to contain content.

An empty span or div could be used, for instance, but this usage looks and smells degenerate.

One thought is to use the wbr element for this purpose. The wbr has an empty content model and simply declares that a line break is possible; this is still a slightly gratuitous use of a markup tag, but much less so than gratuitous document divisions or empty text spans.

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看风景的人
4楼-- · 2018-12-31 04:22

According to the HTML 5 specification, 5.9.8 Navigating to a fragment identifier:

For HTML documents (and the text/html MIME type), the following processing model must be followed to determine what the indicated part of the document is.

  1. Parse the URL, and let fragid be the <fragment> component of the URL.
  2. If fragid is the empty string, then the indicated part of the document is the top of the document.
  3. If there is an element in the DOM that has an ID exactly equal to fragid, then the first such element in tree order is the indicated part of the document; stop the algorithm here.
  4. If there is an a element in the DOM that has a name attribute whose value is exactly equal to fragid, then the first such element in tree order is the indicated part of the document; stop the algorithm here.
  5. Otherwise, there is no indicated part of the document.

So, it will look for id="foo", and then will follow to name="foo"

Edit: As pointed out by @hsivonen, in HTML5 the a element has no name attribute. However, the above rules still apply to other named elements.

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余生无你
5楼-- · 2018-12-31 04:25

There's no semantic difference; the trend in the standards is toward the use of id rather than name. However, there are differences that may lead one to prefer name in some cases. The HTML 4.01 specification offers the following hints:

Use id or name? Authors should consider the following issues when deciding whether to use id or name for an anchor name:

  • The id attribute can act as more than just an anchor name (e.g., style sheet selector, processing identifier, etc.).
  • Some older user agents don't support anchors created with the id attribute.
  • The name attribute allows richer anchor names (with entities).
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一个人的天荒地老
6楼-- · 2018-12-31 04:28

Wikipedia makes heavy use of this feature like this:

<a href="#History">[...]</a>
<span class="mw-headline" id="History">History</span>

And Wikipedia is working for everybody, so I would feel safe sticking with this form.

Also don't forget, you can use this not only with spans but with divs or even table cells, and then you have access to the :target pseudo-class on the element. Just watch out not to change the width, like with bold text, cause that moves content around, which is disturbing.

Named anchors - my vote is to avoid:

  • "Names and ids are in the same namespace..." - Two attributes with the same namespace is just crazy. Let's just say deprecated already.
  • "Anchors elements without href atribute" - Yet again, the nature of an element (hyperlink or not) is defined by having an atribute?! Double crazy. Common sense says to avoid it altogether.
  • If you ever style an anchor without a pseudo-class, the styling applies to each. In CSS3 you can get around this with attribute selectors (or same styling for each pseudoclass), but still it's a workaround. This usually doesn't come up because you choose colors per pseudo-class, and the underline being present by default it only makes sense to remove, which makes it the same as other text. But you ever decide to make your links bold, it'll cause trouble.
  • Netscape 4 might not support the id feature, but still an unknown attribute won't cause any trouble. That's what called compatibility for me.
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初与友歌
7楼-- · 2018-12-31 04:28
<h1 id="foo">Foo Title</h1>

is what should be used. Don't use an anchor unless you want a link.

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