/**************************************************************************************
 Simple date selector expecting 3 HTML selects with ID dayfield, monthfield, yearfield
 Number of calendar days is adjusted with selected month. Leap year proof.
 **************************************************************************************/

var today = new Date();
var monthtext=['Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sept','Oct','Nov','Dec'];

function populate_date(oForm)
{
    var dayfield=document.getElementById("dayfield"); 
    var monthfield=document.getElementById("monthfield");
    var yearfield=document.getElementById("yearfield");
	
    for(x=0;x<12;x++) {
    	monthfield.options[x]= new Option ( monthtext[x], x+1);
    }
	var yr=today.getFullYear();
	for (var y=0; y<3; y++){			
        yearfield.options[y]=new Option(yr, yr);
        yr+=1;
	}		
	monthfield.options[today.getMonth()]=new Option(monthtext[today.getMonth()], today.getMonth()+1, true, true) //select today's month
   	update_days(oForm);
   	dayfield.options[today.getDate()-1]=new Option(today.getDate(), today.getDate(), true, true) //select today's day */
}

function update_days(oForm)
{
    var dayfield=document.getElementById("dayfield"); 
    var monthfield=document.getElementById("monthfield");
    var yearfield=document.getElementById("yearfield");
    
        temp=dayfield.selectedIndex;
        for(x=dayfield.options.length;x>0;x--)
        {
                dayfield.options[x]=null;
         }
        mnth=parseInt(monthfield[monthfield.selectedIndex].value);
        yr=parseInt(yearfield.options[yearfield.selectedIndex].value);
        no_days = 0;
        switch (mnth)
		{			
			case 4:
			case 6:
			case 9:
			case 11:
			  no_days = 30;
			  break;
			case 2:
			  leap(yr)? no_days = 29 : no_days = 28;
			  break;
			default:
			  no_days = 31;
		}     
        for(x=1;x < no_days+1;x++)
        {
            dayfield.options[x-1]=new Option (x, x);
        }
        if (temp == -1) dayfield.options[0].selected=true;
        else
             dayfield.options[temp].selected=true;
}

function leap(y){return(y%4 == 0 && !(y%100 == 0 && !(y%400 == 0)))};