JSFiddle - React, Tailwind, and code Playground

HTML

<form onsubmit="return onFormSubmit(this)">
    Language: <input type="checkbox" name="click_1" value="english" checked />english
                  <input type="checkbox" name="click_2" value="non english">non english</p>
        <input type="submit" />
</form>
<script type="text/javascript">
function onFormSubmit(form_element) {
  if ((form_element.click_1.checked == true && form_element.click_2.checked == true)) {
      alert("Please check only one choice!");
      return false;
  } else if ((form_element.click_1.checked == false && form_element.click_2.checked == false)) {
      alert("Please check your choice!");
      return false;
    }
    return true;
}
</script>