<input name="selecta" type="radio" onclick="selected('a')">
<input name="selecta" type="radio" onclick="selected('b')">
<input name="selecta" type="radio" onclick="selected('c')">

<div id="box">
content
	<div class="a">a</div>
	<div class="a">aa</div>
	<div class="a">aaa</div>

	<div class="b">b</div>
	<div class="b">bb</div>
	<div class="b">bbb</div>

	<div class="c">c</div>
	<div class="c">cc</div>
	<div class="c">ccc</div>
</div>

const classNames = ['a', 'b', 'c'];
function selected(className) {
  const box = document.getElementById('box');
  classNames.forEach(name => {
    if (name === className) {
      [...box.getElementsByClassName(name)].forEach(el => {
        el.ariaHidden = false;
        el.style.display = 'inherit';
      });
    } else {
      [...box.getElementsByClassName(name)].forEach(el => {
        el.ariaHidden = true;
        el.style.display = 'none';
      });
    }
  });
}