如何检查单选按钮是否被选中(javascript、html)

var radioButtons = document.querySelectorAll('input[type="radio"]');
for (var i = 0; i < radioButtons.length; i++) {
  if (radioButtons[i].checked) {
    console.log("单选按钮被选中");
  }
}

var radioButton = document.getElementById('radioButtonId');
if (radioButton.checked) {
  console.log("单选按钮被选中");
}

<input type="radio" id="radioButtonId" onchange="checkRadioButton()">

function checkRadioButton() {
  var radioButton = document.getElementById('radioButtonId');
  if (radioButton.checked) {
    console.log("单选按钮被选中");
  }
}