Place Assets on a Cookie-free Domain

[sukishan]

Place Assets on a Cookie-free Domain

If you set a lot of cookies, the request headers for your pages will increase in size, since those cookies are sent with each request. Additionally, your assets probably don't use the cookies, so all of this information could be repeatedly sent to the client for no reason. Sometimes, those headers may even be bigger than the size of the asset requested -- these are extreme cases of course, but it happens. Consider downloading those small icons or smilies that are less than half a kB, and requesting them with 1kB worth of HTTP headers.

If you use subdomains to host your assets, you need to make sure that the cookies you set are for your canonical domain name (e.g. www.example.org) and not for the top-level domain name (e.g. example.org). This way, your asset subdomains will be cookie-free. If you're attempting to improve the performance of an existing site, and you've already set your cookies on the top-level domain, you could consider the option of hosting assets on new domains, rather than subdomains.