Any JavaScript statement can be identified by a label, but those labels should be used only on 'while', 'do-while' and 'for' statements.

The following code snippet illustrates this rule :

label: // NOK
if (i % 2 == 0) {
  if (i == 12) {
    print("12");
    break label;
  }
  print("Odd number, but not 12");
}

loop: // OK
for (i = 0; i < 10; i++) {
  print("Loop");
  break loop;
}