It is important to understand that when they said "javascript" they almost certainly meant "DOM". All mainstream javascript engines, including Carakan (the curr

It is important to understand that when they said "javascript" they almost certainly meant "DOM". All mainstream javascript engines, including Carakan (the current Opera javascript engine), are very compatible with the standard and with each other. On the other hand, DOM APIs are rather less interoperable across browsers for both historic (lack of clear standards until recently) and technical (larger surface area, faster pace of addition, lack of proper testsuites) reasons. Therefore they are by far the more likely place to run into an interoperability issue.