JSFiddle - React, Tailwind, and code Playground

HTML

<form name="checkbox">
   <p><input type="checkbox" name="a" value="Покупка">Покупка</p>
   <p><input type="checkbox" name="a" value="Аренда"> Аренда</p>
  </form>
  <div id="resultBox">
      <div id="Покупка">Блок с покупкой</div>
      <div id="Аренда">Блок с арендой<div id="test">test</div></div>     
  </div>

CSS

#resultBox > div{
    display: none;
}

JavaScript

var resultBox = document.getElementById('resultBox');
var form = document.checkbox;
form.onclick = toShow;
function toShow(e) {
    event = e || window.event;
    target = event.target || event.srcElement;
    if(target.type == 'checkbox'){
        alert(target.checked);
//        alert(document.getElementById(target.value));
        if(target.checked == true){
            document.getElementById(target.value).style.display = 'block';
        }else{
            document.getElementById(target.value).style.display = 'none';
        }
    }
}