<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=windows-1251" />
<title>Untitled Document</title>
</head>
<script type="text/javascript" language="javascript">
function checkYear() {
var d=new Date();
var year=d.getFullYear();
return (((year % 4 == 0) && (year % 100 != 0)) || (year % 400 == 0)) ? true : false;
}
function changer(s){
switch(s.value){
case "1":document.getElementById('option28').style.visibility='visible';
document.getElementById('option29').style.visibility='visible';
document.getElementById('option30').style.visibility='visible';
document.getElementById('option31').style.visibility='visible';
return true;
case "2":document.getElementById('option28').style.visibility='visible';
document.getElementById('option29').style.visibility=(checkYear())?'visible':'hidden';
document.getElementById('option30').style.visibility='hidden';
document.getElementById('option31').style.visibility='hidden';
return true;
case "3":document.getElementById('option28').style.visibility='visible';
document.getElementById('option29').style.visibility='visible';
document.getElementById('option30').style.visibility='visible';
document.getElementById('option31').style.visibility='visible';
return true;
case "4":document.getElementById('option28').style.visibility='visible';
document.getElementById('option29').style.visibility='visible';
document.getElementById('option30').style.visibility='visible';
document.getElementById('option31').style.visibility='hidden';
return true;
case "5":document.getElementById('option28').style.visibility='visible';
document.getElementById('option29').style.visibility='visible';
document.getElementById('option30').style.visibility='visible';
document.getElementById('option31').style.visibility='visible';
return true;
case "6":document.getElementById('option28').style.visibility='visible';
document.getElementById('option29').style.visibility='visible';
document.getElementById('option30').style.visibility='visible';
document.getElementById('option31').style.visibility='hidden';
return true;
case "7":document.getElementById('option28').style.visibility='visible';
document.getElementById('option29').style.visibility='visible';
document.getElementById('option30').style.visibility='visible';
document.getElementById('option31').style.visibility='visible';
return true;
case "8":document.getElementById('option28').style.visibility='visible';
document.getElementById('option29').style.visibility='visible';
document.getElementById('option30').style.visibility='visible';
document.getElementById('option31').style.visibility='visible';
return true;
case "9":document.getElementById('option28').style.visibility='visible';
document.getElementById('option29').style.visibility='visible';
document.getElementById('option30').style.visibility='visible';
document.getElementById('option31').style.visibility='hidden';
return true;
case "10":document.getElementById('option28').style.visibility='visible';
document.getElementById('option29').style.visibility='visible';
document.getElementById('option30').style.visibility='visible';
document.getElementById('option31').style.visibility='visible';
return true;
case "11":document.getElementById('option28').style.visibility='visible';
document.getElementById('option29').style.visibility='visible';
document.getElementById('option30').style.visibility='visible';
document.getElementById('option31').style.visibility='hidden';
return true;
case "12":document.getElementById('option28').style.visibility='visible';
document.getElementById('option29').style.visibility='visible';
document.getElementById('option30').style.visibility='visible';
document.getElementById('option31').style.visibility='visible';
return true;
default:return false;
}
}
</script>
<body>
<select onchange="changer(this);">
<option value="" selected="selected">---</option>
<option value="1">Януари</option>
<option value="2">Февруари</option>
<option value="3">Март</option>
<option value="4">Април</option>
<option value="5">Май</option>
<option value="6">Юни</option>
<option value="7">Юли</option>
<option value="8">Август</option>
<option value="9">Септември</option>
<option value="10">Октомври</option>
<option value="11">Ноември</option>
<option value="12">Декември</option>
</select><br />
<select>
<option>1</option>
<option>2</option>
<option>3</option>
<option>4</option>
<option>5</option>
<option>6</option>
<option>7</option>
<option>8</option>
<option>9</option>
<option>10</option>
<option>11</option>
<option>12</option>
<option>13</option>
<option>14</option>
<option>15</option>
<option>16</option>
<option>17</option>
<option>18</option>
<option>19</option>
<option>20</option>
<option>21</option>
<option>22</option>
<option>23</option>
<option>24</option>
<option>25</option>
<option>26</option>
<option>27</option>
<option id="option28">28</option>
<option id="option29">29</option>
<option id="option30">30</option>
<option id="option31">31</option>
</select>
</body>
</html>