break continue

1. 都可以用于循环
2. break还可以用于switch语句及跳出代码块

---continue---
i = 0;
n = 0;
while (i < 5) {
   i++;
   if (i === 3) {
      continue;
   }
   n += i;
}
......................
var i = 0, 
    j = 8;

checkiandj: while (i < 4) {
   console.log("i: " + i);
   i += 1;

   checkj: while (j > 4) {
      console.log("j: "+ j);
      j -= 1;
      if ((j % 2) == 0)
         continue checkj;
      console.log(j + " is odd.");
   }
   console.log("i = " + i);
   console.log("j = " + j);
}

---break---
var i = 0;
while (i < 6) {
  if (i == 3) {
      break;
  }
  i += 1;
}
................
outer_block:{
  inner_block:{
    console.log ('1');
    break outer_block;      // breaks out of both inner_block and outer_block
    console.log (':-(');    // skipped
  }
  console.log ('2');        // skipped
}