Javascript multiple assignment statement

Question

I saw that line in some code

window.a = window.b = a;

How does it work?

Does the following always return true?

win

Answer 1

It's the same like:

window.b=a;
window.a= window.b;

window.a == a will be true in this case, after the statements above. There are some cases that it will be false, for example: when a is a global variable.

And one more thing: please find more informative title for your question next time.