// this version (JavaScript1.1+) does NOT display NaN.
function DSTCalc() {
    var thisYear, AprilDate, OctoberDate, MarchDate, NovemberDate;
    thisYear = Math.round(parseInt(document.forms[1].year.value));

    AprilDate = (2+6 * thisYear - Math.floor (thisYear / 4) ) % 7 + 1;
    OctoberDate=  (31-( Math.floor (thisYear * 5 / 4) + 1) % 7);
     
    MarchDate = 14 - (Math.floor (1 + thisYear * 5 / 4) % 7);
    NovemberDate = 7 - (Math.floor (1 + thisYear * 5 / 4) % 7);
 
    if (document.forms[1].year.value !=null && document.forms[1].year.value.length == 4 && !isNaN(document.forms[1].year.value)) {

	if (parseInt(document.forms[1].year.value) >=2007) {
	
		document.getElementById("startmonth").innerHTML="March";
		document.getElementById("endmonth").innerHTML="November";
	
		if (!isNaN(MarchDate)) document.getElementById("dststart").innerHTML="" + MarchDate;

		if (!isNaN(NovemberDate)) document.getElementById("dstend").innerHTML="" + NovemberDate;
	
	}
	else {
	
		document.getElementById("startmonth").innerHTML="April";
		document.getElementById("endmonth").innerHTML="October";

		if (!isNaN(AprilDate)) document.getElementById("dststart").innerHTML="" + AprilDate;

		if (!isNaN(OctoberDate)) document.getElementById("dstend").innerHTML="" + OctoberDate;
	}

    }

}

function DSTCalcSubmit() {
    
    return false;

}