There is, in ‘newer’ versions of Javascript: Destructuring assignment – Javascript 1.7. It’s probably only supported in Mozilla-based browsers, and maybe in Rhino.
var a = 1;
var b = 3;
[a, b] = [b, a];
EDIT: actually it wouldn’t surprise me if the V8 Javascript library (and thus Chrome) supports this. But don’t count on it either
Now supported in all modern browsers(except IE, of course).