10. A system comprising: a communications interface that receives requests for web pages from client devices; and a hardware processor; and a memory storing a set of one or more locale-specific modules that each enable an interface of the client devices to perform one or more locale-specific formatting operations using the web pages when the interfaces render the web pages using one or more scripts associated with the web pages, the memory further storing a set of instructions that when executed by the processor cause the processor to: receive a request for a web page created in a specific language from an interface associated with a client device, the web page comprising content in the specific language, one or more elements in a first markup language used by an interface of the client device to display the content, and one or elements in a second markup language, the second markup language being an intermediate non-scripting language different from the first language; extract a locale-specific preference from a header in the request, the locale-specific preference in the header further including one or more entries that each indicate a preference level for document languages; select a locale-specific module corresponding to the locale-specific preference from the set of locale-specific modules, the selected locale-specific module built in a language supported by a script associated with the requested web page using one or more user-supplied definitions associating an element of the webpage in the second markup language with one or more locale-specific formattings; send the locale-specific module to the client device via the communications interface for storage at the client device; and send the requested web page to the client device via the communications interface for storage at the client device, wherein, when the client device encounters the element of the web page in the second markup language when executing the script, the client device uses the locale-specific module to determine the one or more locale-specific formattings.
13. The system of claim 10 , wherein the locale-specific preference comprises a location preference.