Funny, I hear often that "WASM is just javascript" whenever I compare it to Flash and Java, as a defense for why it is different this time and totally won't have any of the problems of those other runtimes.
Because wasm runs on the same javascript and not as a separate plugin. It will be a major feature of the browser and be automatically updated with it. (also it allows for feature discovery)
It has no relation to ecmascript, but you could say that it is integrated in (but independent from) javascript.
People say that it is not javascript because you can use ALL of the wasm toolchain without any trace of javascript.
