Why doesn't this crazy brackety Javascript cause a syntax error?

Question

I was playing around with some Javascript snippets today and noticed that this code would actually run:

{{for(var i = 0; i < 3; i++) {{{{
  alert(i);
}}}}}}

You can try it out for yourself on jsFiddle.

Why does this run without any syntax errors? What do the repeated brackets mean? Does Javascript just ignore repeated curly braces?

Answer 1

It creates a new block, which is effectively useless¹ because JavaScript doesn't have block scope².

_{¹ This is a beautiful oxymoron.
² Yet.}