Javascript How to define multiple variables on a single line?

Question

Reading documentation online, I\'m getting confused how to properly define multiple JavaScript variables on a single line.

If I want to condense the following code,

Answer 1

There is no way to do it in one line with assignment as value.

var a = b = 0;

makes b global. A correct way (without leaking variables) is the slightly longer:

var a = 0, b = a;

which is useful in the case:

var a = , b = a, c = a, d = a;