<form>
  <label for="choice1">选择1</label>
  <input type="checkbox" id="choice1" name="choice1">
  <br>
  <label for="choice2">选择2</label>
  <input type="checkbox" id="choice2" name="choice2">
  <br>
  <input type="submit" value="提交">
</form>

<script>
  document.querySelector('form').addEventListener('submit', function(event) {
    event.preventDefault(); // 阻止表单的默认提交行为

    var choice1 = document.querySelector('#choice1');
    var choice2 = document.querySelector('#choice2');

    if (choice1.checked && choice2.checked) {
      window.location.href = 'URL1'; // 如果选择标记1和标记2都被选中，则跳转到URL1
    } else if (choice1.checked) {
      window.location.href = 'URL2'; // 如果只选择了标记1，则跳转到URL2
    } else if (choice2.checked) {
      window.location.href = 'URL3'; // 如果只选择了标记2，则跳转到URL3
    } else {
      window.location.href = 'URL4'; // 如果都未选择，则跳转到URL4
    }
  });
</script>