Variable scope in loops

Question

I am a bit confused http://jsfiddle.net/

{
 for (var counter = 1; counter < 6; counter++) {
 }
}
console.log(counter);

If variables from loops are available in the scope the for loop is created, then why do I have access to the variable one level higher, since I created another scope by putting those brackets?

• Luaan: Javascript only knows object scope and function scope. There's no block scope.
• T J: Variables have function level scope, not block level...
• George Irimiciuc: Ah, now I understand.

Answer 1

Variables created with the var keyword have function scope (or global scope if they're declared outside of a function).

ES6 introduces the let keyword for block scoped variables.

Answer 2

Loops do not have their own scopes.

A loop is a block, and blocks do not have their own scopes; variables created with var can only have function or global scope.

As others have pointed out, in ES6, you will be able to use block-scoped variables with the let keyword.

• George Irimiciuc: I know, the scope is the same as the one in which they were created. Maybe I'm wrong?
• elixenide: Yes, you're wrong. If you do for(var counter = 1...), counter will be available from that point forward in the function containing this loop (or globally, if it is not in a function).

Answer 3

You are wrong, loops do not have scopes.