Actually, while it's almost never used (I certainly haven't seen code using it), blocks cooperate with labels too. The following is perfectly valid: var fn =

Actually, while it's almost never used (I certainly haven't seen code using it), blocks cooperate with labels too. The following is perfectly valid: var fn = function() { nowWeDance: { dance(); } }; The block uses the same execution context and scope, of course, so it's not useful. A block is legal alone too: (function() { { return 1; } })(); // 1 I suppose for a very long switch statement (god forbid), blocks could be useful: switch (x) { case 1: { // do stuff break; } case 2: { // do stuff break; } } But I wouldn't favor it because it makes the break seem implicit to the reader when it in fact is not.