圓形按鈕

已勾選，已停用 
<div>
  <input type="radio" name="radio-a" id="radio1" checked>
  <label for="radio1">Checked</label>
</div>
<div>
  <input type="radio" name="radio-a" id="radio2">
  <label for="radio2">Unchecked</label>
</div>
<div>
  <input type="radio" name="radio-b" id="radio3" checked disabled>
  <label for="radio3">Checked, disabled</label>
</div>
<div>
  <input type="radio" name="radio-b" id="radio4" disabled>
  <label for="radio4">Unchecked, disabled</label>
</div>