[whatwg] [The Module Tag

[Douglas Crockford]

> > The sender is suspended until the receiver returns.

> As a quick note, in general we're trying to get away from synchronous 
> scripting. It causes too many problems, especially in browsers written 
> around a single UI thread on which JS runs. Several APIs are having to be 
> grandfathered in -- window.alert(), for instance -- but as a rule none of 
> the new APIs should be synchronous.

This is a function invocation. The new APIs should allow function invocations to remain synchronous. The thing to avoid is blockage. alert() is evil. send() is not.