We present an approach to multilingual web content based on
multilingual grammars and syntax editing for a controlled language.
Content can be edited in any supported language and it is
automatically kept within a controlled language fragment.  We have
implemented a web-based syntax editor for Grammatical Framework (GF)
grammars which allows both direct abstract syntax tree manipulation
and text input in any of the languages supported by the grammar.  With
this syntax editor and the GF JavaScript API, GF grammars can be used
to build multilingual web applications. As a demonstration, we have
implemented an example application in which users can add, edit and
review restaurants in English, Spanish and Swedish.