如何访问另一个表单上的复选框？

<form id="form1">
  <input type="checkbox" id="checkbox1" name="checkbox1" value="option1">选项1
</form>

<form id="form2">
  <input type="checkbox" id="checkbox2" name="checkbox2" value="option2">选项2
</form>

<button onclick="checkCheckbox()">检查复选框状态</button>

function checkCheckbox() {
  var checkbox1 = document.getElementById("checkbox1");
  var checkbox2 = document.getElementById("checkbox2");

  if (checkbox1.checked) {
    console.log("复选框1被选中");
  } else {
    console.log("复选框1未被选中");
  }

  if (checkbox2.checked) {
    console.log("复选框2被选中");
  } else {
    console.log("复选框2未被选中");
  }
}