代码示例:(标识:jsck_state_break_label_nest)
<!DOCTYPE html>
<html>
<body>

<p>在本例中,break 语句引用标记为 "Loop1" 的 for 循环。当 j 等于 2 时,break 语句“跳出” Loop1。</p>

<button onclick="myFunction()">试一试</button>

<p id="demo"></p>

<script>
function myFunction() {
  var text = "";
  var i, j;

  Loop1:         // 标记为 "Loop1" 的第一个 for 循环
  for (i = 0; i < 3; i++) {
  text += "<br>" + "i = " + i + ", j = ";
  
    Loop2:       // 标记为 "Loop2" 的第二个 for 循环
    for (j = 0; j < 5; j++) {
      if (j === 2) {
        break Loop1;
      }
      document.getElementById("demo").innerHTML = text += j + " ";
    }
  }
}
</script>

</body>
</html>
运行结果: