cross origin requests are only supported when a web-browser supports it. Firefox and Safari are the two browsers that support cross origin requests. The other browsers will only be able to support cross origin requests when they are being used with a server that has the ability to handle the request (i.e., a web server).
This isn’t to say that developers should not make cross origin requests, but it can be a lot of work to make sure that your site is not being used for other sites’ cross origin requests. It’s also a problem when you have a web site of yours that uses cross origin requests such as Facebook, Twitter, and so on. I once had a site that used cross origin requests, but I didn’t have a way to fix it.
When you have a web site that makes use of cross origin requests, you have to check if it is actually used by any other sites. You can check that by checking for cross origin requests on the server that owns your site. I wrote a tool for that last year and it works quite well. If you have a web site that you want to use other sites with, you can also check to see if they are using cross origin requests.
It’s definitely a good idea to make sure that your visitors can find your site if they visit a lot of different sites. However, it’s also important to remember that cross origin requests may not be used by all of the other sites. If a site you are linking to requires cross origin requests, you can check if that is the case.
That last point means that cross origin requests are only supported for sites that have a very unique way of linking to each other. For example, if you have a site with a unique way of linking to a site, you can check to see if cross origin requests are indeed supported there.
Yes, cross origin requests might not be used by all of the other sites, but your links will still be valid. When someone creates a page and wants their own site to link to it, they can create a cross origin request. They can simply paste their site URL in the middle of the link and then request the other site to redirect their domain to yours. In other words, cross origin requests allow you to link to a third party without having to worry about which site has the URL.
We’re not sure whether cross origin requests are going to be implemented in all of the other major search engines, but for now at least, they’re pretty much in place.
As always, cross origin requests are just one of the many ways to link a site. If you know your sites are on the same domain, you can also do a cross origin request on the site of your choice and get your site to link to your domain name.
If you’re not currently aware of cross origin requests, I recommend you check out a tutorial for how to do it.
If you do cross origin requests, your sites will most likely still be on the same domain, but you should probably make sure that you have a domain name to link to. If your site has that, you can do a cross origin request, and your site will most likely link to your domain name as well.