You can only break
a block scope if you label it. For example:
myBlock: {
var a = 0;
break myBlock;
a = 1; // this is never run
};
a === 0;
You cannot break a block scope from within a function in the scope. This means you can't do stuff like:
foo: { // this doesn't work
(function() {
break foo;
}());
}
You can do something similar though with functions:
function myFunction() {myFunction:{
// you can now use break myFunction; instead of return;
}}