var mdays = new Array(31,28,31,30,31,30,31,31,30,31,30,31);
var mdaysv = new Array(31,29,31,30,31,30,31,31,30,31,30,31);

function AjustMon(form,field,fday)
{
var yrfld = byid('yr_'+field);
var mnfld = byid('mn_'+field);
var dnfld = byid('dn_'+field);
fyear = yrfld.value;
fmon = mnfld.value;
if (!fday)
   { fday = dnfld.value; }

dnfld.options.length=0;
var oOption = document.createElement("OPTION");
dnfld.options.add(oOption);
oOption.innerHTML = "δενό";
oOption.value = 0;

if (fyear == 0 || fmon == 0)
   { return; }
mon = fmon - 1;
year = fyear;
if (year % 4)
   { mtop = mdays[mon]; }
else
   { mtop = mdaysv[mon]; }
if (mtop < fday)
   { fday = mtop;	}
mtop++;

for (j = 1; j < mtop; j++)
   {
	var oOption = document.createElement("OPTION");
	dnfld.options.add(oOption);
	oOption.innerHTML = j;
	oOption.value = j;
	if (j == fday)
   	{ oOption.selected = true; }	
	}
}