Is JavaScript guaranteed to be single-threaded?

Question

JavaScript is known to be single-threaded in all modern browser implementations, but is that specified in any standard or is it just by tradition? Is it totally safe to assu

Answer 1

@Bobince is providing a really opaque answer.

Riffing off of Már Örlygsson's answer, Javascript is always single-threaded because of this simple fact: Everything in Javascript is executed along a single timeline.

That is the strict definition of a single-threaded programming language.