如何使用Javascript验证Radio

Question

我的代码HTML

<input type="radio" class="w3-radio" name="ket_jawaban[<?php echo $no2;?>]" value="<?php echo $row->pil1;?>"  oninput="this.className = ''"> <?php echo $row->pil2;?>
<input type="radio" class="w3-radio" name="ket_jawaban[<?php echo $no2;?>]" value="<?php echo $row->pil2;?>" oninput="this.className = ''"> <?php echo $row->pil2;?>
<input type="radio" class="w3-radio" name="ket_jawaban[<?php echo $no2;?>]" value="<?php echo $row->pil3;?>" oninput="this.className = ''"><?php echo $row->pil3;?>
<input type="radio" class="w3-radio" name="ket_jawaban[<?php echo $no2;?>]" value="<?php echo $row->pil4;?>" oninput="this.className = ''"><?php echo $row->pil4;?>
<input type="radio" class="w3-radio" name="ket_jawaban[<?php echo $no2;?>]" value="<?php echo $row->pil5;?>" oninput="this.className = ''"> <?php echo $row->pil5;?>

我的Javascript验证

function validateForm() {
  // This function deals with validation of the form fields
  var x, y, i, valid = true;
  x = document.getElementsByClassName("tab");
  y = x[currentTab].getElementsByTagName("*");
  // A loop that checks every input field in the current tab:
  for (i = 0; i < y.length; i++) {
    // If a field is empty...
    if (y[i].value == "" || !y[i].checked) {
      // add an "invalid" class to the field:
      y[i].className += " invalid";
      // and set the current valid status to false
      valid = false;
    }
  }
  // If the valid status is true, mark the step as finished and valid:
  if (valid) {
    document.getElementsByClassName("step")[currentTab].className += " finish";
  }
  return valid; // return the valid status
}

如何修复验证无线按钮的这个问题？

此代码可以验证输入类型文本，但不能验证类型单选...我想我在这段代码中的问题!y[i].checked请帮我解决它

这是镜像我的程序enter image description here