问HTML (或jQuery)：选择一个或两个复选框(或单选按钮)

EN

<input type="checkbox" class="at-least-one">
<input type="checkbox" class="at-least-one">

<script type="text/javascript">
$(document).on("click", ".at-least-one", function(evt) {
  // This is technically run after the checked value changes, so we're checking
  //   if there is no more boxes checked after we uncheck this one. If there is
  //   no more, then prevent the event, setting the box back to checked.
  if ($(".at-least-one:checked").length == 0) {
    evt.preventDefault()
    return false
  }
})  
</script>

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<p>One checkbox must always be checked</p>
<input type="checkbox" name="checkone" checked>
<input type="checkbox" name="checkone" checked>
<script>
$('input[name=checkone]').click(function(e){
  if(!$('input[name=checkone]:checked').length){
   return false;
  }
});
</script>