Behaviour of <link rel=alternate> in browsers

StackOverflow https://stackoverflow.com/questions/22152428

  •  19-10-2022
  •  | 
  •  

Question

I am a bit confused about the behavior of <link rel="alternate" ...> in browsers and i am looking for some clarification. Let's use the following code for illustration:

<!DOCTYPE html>
<html lang="en">
    <head>
        <link rel="stylesheet" href="a.css" type="text/css" 
              title="Main Stylesheet">
        <link rel="alternate stylesheet" href="b.css" type="text/css" 
              title="Alternative Stylesheet">
        <link rel="alternate" href="fr.pdf" hreflang="fr" type="application/pdf" 
              title="Alternative document in French">
    </head>
    <body>
    </body>
</html>

When this code runs in a modern browser (e.g. Firefox v27.01), the browser parses the above HTML document and then downloads the stylesheets, a.css and b.css. The former is used to apply the style to the document. However, b.css is available through the 'View > Page Style' menu of the said browser. So, clearly the parser in Firefox is able to recognize the "alternative" stylesheet and in this case decided to download it.

One can read at W3C > HTML5 > 4.8.4.1 that the outcome of parsing those <link>s are basically hyperlinks referencing the respective document. In the case of stylesheet, the browser is smart enough to download it as well. But, for the other alternate document (fr.pdf) in our example, it looks like Firefox does not download it and if it links it, it is not visible anywhere. I tested in Chrome (v.33.0.1750.117), Opera (v.19.0.1326.63), IE (v.10.0.9200.16798) and could observe same thing (i.e. no visible artifact that the fr.pdf has been linked). So, as all those modern browsers behave like this, it looks like I have misunderstood the meaning of "alternate" relationships:) Would someone have an explanation for me of how they are intended to be used? My belief is that in a RESTful manner, user-agents should be able to (hyper)link all the <link>s in order to navigate that web.

Thanks in advance.

No correct solution

OTHER TIPS

The <link> element does indeed identify external documents that are related to the current document. And the rel attribute specifies the nature of that relationship. In the specific case of rel="alternate stylesheet" (some) browsers can do something specific with the link. In particular, Firefox and Opera give the user a chance to select this "alternate" stylesheet from the application's menu. See, e.g., the screen shot

from this article.

In order to apply that style sheet, the browser needs to download it.

In the more general case of rel="alternate" (not a stylesheet), then the browser won't know anything useful to do with the related link. Therefore, as far as the browser is concerned, there's no need to download it.

Licensed under: CC-BY-SA with attribution
Not affiliated with StackOverflow
scroll top