<form action="oku.php" method="post" class="formArea">
  
<div class="firstArea">
<p class="sorular"> <b>Cinsiyetiniz</b></p>

<div class="form-check form-check-inline">
<input class="form-check-input" type="radio" name="Cinsiyetiniz" id="inlineRadio1" value="Kız" required>
<label class="form-check-label" for="inlineRadio1">Kız</label>
</div>
<div class="form-check form-check-inline">
<input class="form-check-input" type="radio" name="Cinsiyetiniz" id="inlineRadio2" value="Erkek" required>
<label class="form-check-label" for="inlineRadio2">Erkek</label>
</div></div>

<button> Devam </button>

<div class="secondArea">
<p class="sorular"><b>Annenizin Mesleği</b></p>

<div class="form-check form-check-inline">
<input class="form-check-input" type="radio" name="anne_meslegi" id="anne_meslek1" value="Ev Hanımı" onclick="ajaxValidate(this)"required>
<label class="form-check-label" for="anne_meslek1">Ev Hanımı</label>

  
       </div></div>
      
       <br><br>
       <button type="submit">Gönder</button>
        
    </form>

    
        document.querySelector(".secondArea").style.display = "none";
    
        document.querySelector(".formArea button").addEventListener('click', function(e) {
            
            e.preventDefault();
            
             document.querySelector(".secondArea").style.display = "block";
             document.querySelector(".firstArea").style.display = "none";
            
            document.querySelector('.formArea button').style.display = "none";

        })