What are Gecko's Javascript interpreter engine semantics?

Question

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In consideration of the answer response below regarding the reference ECMAScript Language Specification - 11.13.2 Compound Assignment

Considering why thes

Answer 1

JavaScript has an eager evaluation (call by value) execution model clearly spelled out in the ECMA standard. All of these questions can be resolved by carful reading of the standard. For example, the reason why the result is 11 above and not 12 is clearly spelled out in 11.13.2 of the standard. o.n is evaluated prior to the call to f() not after as specified by step 2.