<html>
<head>
<script language="javascript" type="text/javascript">
function resmies(){ document.getElementById('miesiac').value='';
document.getElementById('dzien').value=''; }
function dlugim(mm) { r=document.getElementById('rok').value;
dd=0;
if ((r%4)==0){dd=1;}
if ((mm==01)||(mm==03)||(mm==05)||(mm==07)||(mm==08)||(mm==10)||(mm==12)){dn=31;document.getElementById('dzien').length=31;
document.getElementById('dzien').options['28'].value=29;
document.getElementById('dzien').options['28'].text=29;
document.getElementById('dzien').options['29'].value=30;
document.getElementById('dzien').options['29'].text=30;
document.getElementById('dzien').options['30'].value=31;
document.getElementById('dzien').options['30'].text=31;
}
if ((mm==02)&&(dd===1)) {dn=29;document.getElementById('dzien').length=dn; document.getElementById('dzien').options['28'].value=29;
document.getElementById('dzien').options['28'].text=29;
}
if ((mm==02)&&(dd!==1)) {dn=28;document.getElementById('dzien').length=dn;}
if ((mm==04)||(mm==06)||(mm==09)||(mm==11)){dn=30;document.getElementById('dzien').length=30;
document.getElementById('dzien').options['28'].value=29;
document.getElementById('dzien').options['28'].text=29;
document.getElementById('dzien').options['29'].value=30;
document.getElementById('dzien').options['29'].text=30;
}
}
function pobierzdate(){ r=document.getElementById('rok').value;
m=document.getElementById('miesiac').value;
dz=document.getElementById('dzien').value;
if (dz.length==1) {dz="0"+dz;}
dat=r+"-"+m+"-"+dz;
alert (dat);
}
</script>
</head>
<body>
<SELECT name="rok" size="1"onchange="resmies();" >
<option value="2009">2009</option>
<option value="2010">2010</option>
<option value="2011">2011</option>
<option value="2012">2012</option>
<option value="2013">2013</option>
<option value="2014">2014</option>
<option value="2015">2015</option>
<select>
<SELECT name="miesiac" size="1" onchange="dlugim(this.value);">
<option name="m1" value="01">01</option>
<option name="m2" value="02">02</option>
<option name="m3" value="03">03</option>
<option name="m4" value="04">04</option>
<option name="m5" value="05">05</option>
<option name="m6" value="06">06</option>
<option name="m7" value="07">07</option>
<option name="m8" value="08">08</option>
<option name="m9" value="09">09</option>
<option name="m10" value="10">10</option>
<option name="m11" value="11">11</option>
<option name="m12" value="12">12</option>
<select>
<SELECT name="dzien" size="1" value=""> <?PHP
$dm=31;
FOR ($ild=1;$ild<=$dm;$ild++) {
if($ild<10) {$ild_zero="0";$ild_zero.=$ild;}else{$ild_zero=$ild;}
print("<option value=\"$ild_zero\">$ild_zero\n"); }
?>
<select>
<br>
</body>
</html>