从本地存储中将复选框值插入回表单

<form id="myForm">
  <input type="checkbox" name="option1" value="value1"> Option 1<br>
  <input type="checkbox" name="option2" value="value2"> Option 2<br>
  <input type="checkbox" name="option3" value="value3"> Option 3<br>
  <input type="button" value="Submit" onclick="saveData()">
</form>

function saveData() {
  var form = document.getElementById("myForm");
  var checkboxes = form.getElementsByTagName("input");
  var selectedValues = [];

  for (var i = 0; i < checkboxes.length; i++) {
    if (checkboxes[i].type === "checkbox" && checkboxes[i].checked) {
      selectedValues.push(checkboxes[i].value);
    }
  }

  localStorage.setItem("selectedValues", JSON.stringify(selectedValues));
}

window.onload = function() {
  var form = document.getElementById("myForm");
  var checkboxes = form.getElementsByTagName("input");
  var selectedValues = JSON.parse(localStorage.getItem("selectedValues"));

  if (selectedValues) {
    for (var i = 0; i < checkboxes.length; i++) {
      if (checkboxes[i].type === "checkbox" && selectedValues.includes(checkboxes[i].value)) {
        checkboxes[i].checked = true;
      }
    }
  }
}