问获取JavaScript中复选框的所有值

EN

if ($('input:checkbox').prop('checked').size() == 0)
{
alert('no checkboxes were checked');
}

// utility function
function toArray(obj) {
  var arr = [];
  for (var i = 0, len = obj.length; i < len; i++) {
    arr[i] = obj[i];
  }
  return arr;
}

// get the form
var someForm = ...;
// get all elements and check whether any has type "checkbox" and is checked.
var checked = toArray(someForm.elements).some(function (el) {
  return el.type === "checkbox" && el.checked;
});

if (!checked) {
  alert("please check a box");
}