Interesting discussion happening on Google Webmaster Central regarding Google's approach to crawling websites and the simplicity of migration.

Relative vs Absolute Paths

Differences Between Relative and Absolute Paths
In the world of web development, the choice between using relative paths and absolute paths is a common discussion. Some argue that relative paths are easier to work with when offline and then uploading a website. Meanwhile, others point out the advantages of absolute paths in certain situations.

When it comes to changing domain names while maintaining your website, absolute links may be the way to go. By making changes only to the absolute URLs referenced, you can ensure that your site continues to function properly even after a domain switch.

The Advantages of Using Absolute Paths
One key advantage highlighted by proponents of absolute paths is the ability to optimize page load speeds by utilizing subdomains. By hosting CSS or other files on separate domains like "http://css.example.com/style.css," developers can bypass browser limitations on simultaneous downloads and improve overall performance.

However, it's essential to use caution with absolute paths, particularly when making AJAX calls. Hardcoding specific URLs into JavaScript can lead to issues with the same origin policy, resulting in successful calls from one URL but not another. For example, an AJAX call set to "http://www.example.com/ajaxfile.php" may work from "http://www.example.com/index.php" but fail from "http://example.com/index.php."

One explanation could be personal preference, or maybe it's all about portability. If your files are linked with a complete URL, there's no need to include those files when using the html on another platform; it will automatically fetch them from the remote site.

In my experience, the choice often depends on the platform being used. For instance, in .Net, the symbol ~/ represents the application root, which translates to /path/file.css in the HTML. This might just be because it's simpler and more convenient for developers to work with this path structure.

Another scenario is when you're loading resources from a different domain, like sstatic.net here. In such cases, you aren't left with much of a choice - the links must be fully qualified to ensure proper loading.

Personally, I believe it comes down to individual choice. I lean towards relative URLs as they are easier to modify when switching (sub)domains. However, in the case of using a CMS or blog, this task is typically automated for you (e.g. {SITE_URL}/path/to/page).

It seems that certain Apache Redirect Rules may encounter issues with relative paths. Opting for the absolute path guarantees that the .htaccess file will be accessed.

While I can't speak for those particular websites, it is common practice to use different URLs for static resource files in order to improve efficiency rather than personal preference. Many browsers have a restriction on the number of concurrent connections to a single URL when loading a page, so serving some files from a different URL with an absolute path can bypass this limitation. This strategy helps speed up page load times and is widely adopted in web development.

While portability can be cumbersome, using absolute paths may not always be the best choice when content resides on the same domain. This can lead to unnecessary DNS lookups in some browsers. Opting for relative paths rooted within your site can enhance performance, unless you utilize a CDN or distinct domains for hosting static content.

Trust this information proves valuable!

At times, in server-side code, there might be a variable responsible for displaying the complete URL. My recollection suggests that this is often seen in WordPress themes as they correctly display the directory.

There are differing opinions on whether paths starting from a domain's root (for example, /styles/style.css) should be considered absolute and potentially problematic.

Here's the deal: both fully relative and fully qualified schemes address issues related to relocating files or content. However, they tackle different types of problems. A fully relative scheme allows you to easily move everything associated with a document to a new location on the server without causing any issues. On the other hand, using a fully qualified (and certain absolute) scheme enables you to move individual documents without breaking anything.

Personally, I often find myself moving content in batches rather than migrating individual documents, which is why I prefer utilizing fully relative schemes. Of course, everyone's needs may vary.

I've often been told that using relative URLs within the same domain is beneficial for SEO optimization. I'm not sure if this advice is outdated or still relevant, but it's the explanation I always hear.

To work around this issue, I make use of the base attribute in my header so that I can take advantage of relative URLs. This allows me to easily test on my development server and simply adjust the base URL when needed. However, all relative URLs must be written as if they are starting from the base URL set.

When your page is accessed through the secure https protocol, all relative path stylesheets will also be loaded using the same secure protocol. Do you really need to encrypt or decrypt the css contents? :D

Alternatively, if you opt for an absolute path that points to an external stylesheet, you have the option to specify the protocol to use, which is typically http rather than https.

When it comes to the application you're developing, the approach can vary. For instance, if your application utilizes an MVC framework similar to the one in the given example, absolute paths may be necessary due to the CSS not being associated with the relative path on each page.

EDIT

Although using an MVC framework doesn't strictly require absolute paths, you also have the option to utilize relative paths. It ultimately boils down to personal preference.