The SetLocale function sets the LCID (locale ID).

There is one mandatory argument, the LCID, which is a short string, decimal value, or hex value that uniquely identifies a geographic locale. The various geographic locales are based upon the user's language, country, and culture. For example, the locale "English - United States" can be designated as either "en-us", or "1033", or "0x0409".

This locale information is used to establish user preferences and formats for such things as alphabets, currency, dates, keyboard layout, and numbers,

If the LCID is set to zero, the locale will be set by the system.

Code:
<% =SetLocale(0) %>

Output:
1033