The power of modern websites emerges to a large extent from the ability to combine content from different sources. As an example, a site may include a Google map next to business information a user had been searching for. Combining content from possibly untrusted sites gives rise to all sorts of security concerns, as JavaScript has no concept of separating scripts from different sources. This has lead to several recent attacks like the Samy or Yamanner worms. This talk presents the state of the art in securing JavaScript for such settings and proposes a sandboxing facility for in-browser script separation.