When you visit a website, your browser sends these values to help the server decide which version of a page to serve. If a server sees 0.9,en-us , it understands that US English is a high priority (90% preference) but perhaps second to another language set at 1.0 .
In a standard HTTP request, you might see a header like this: Accept-Language: fr-CH, fr;q=0.9, en;q=0.8, de;q=0.7, *;q=0.5 0.9,en-us
: Refers to the language code for English as used in the United States. When you visit a website, your browser sends
: Developers often look for this string in "Network" tab logs when debugging why a site is displaying the "wrong" language or failing to load localized resources. Other Contexts When you visit a website