<body>
<div id="mainDiv" class="mainDiv">
<input type="button" value="Pobierz dane" onclick="initLbAutors();">
<br><br>
<select id="lbAutors" style="width:250px;" disabled
        onchange="lbAutorsChange()">
<option>Lista autorów</option>
</select>
<br><br>
<select id="lbBooks" style="width:250px;" disabled
        onchange="lbBooksChange()">
<option>Lista książek</option>
</select>
</div>
<div id="dataDiv" class="dataDiv">
</div>
</body>