var timerID ;

function tzone(tz, os, ds, cl)

{

	this.ct = new Date(0) ;		// datetime
	this.tz = tz ;			// code
	this.os = os ;			// GMT offset
	this.ds = ds ;			// has daylight savings
	this.cl = cl ;			// font color

}


function UpdateClocks()

{
	// www.timeanddate.com/worldclock

	var ct = new Array(

		new tzone('ONZ: ', -5, 1, '#FF0000'),
		new tzone('ORD: ', -6, 1, '#000000'),
		new tzone('LAX: ', -8, 0, '#000000'),
		new tzone('ZULU: ', 0, 0, '#000000')

	) ;



	var dt = new Date() ;	// [GMT] time according to machine clock
	var startDST = new Date(dt.getFullYear(), 3, 1) ;

	while (startDST.getDay() != 0)
		startDST.setDate(startDST.getDate() + 1) ;

	var endDST = new Date(dt.getFullYear(), 9, 31) ;

	while (endDST.getDay() != 0)

		endDST.setDate(endDST.getDate() - 1) ;



	var ds_active ;		// DS currently active

	if (startDST < dt && dt < endDST)

		ds_active = 1 ;
	else
		ds_active = 0 ;



	// Adjust each clock offset if that clock has DS and in DS.

	for(n=0 ; n<ct.length ; n++)

		if (ct[n].ds == 1 && ds_active == 1) ct[n].os++ ;



	// compensate time zones

	gmdt = new Date() ;

	for (n=0 ; n<ct.length ; n++)

		ct[n].ct = new Date(gmdt.getTime() + ct[n].os * 3600 * 1000) ;

	document.all.Clock0.innerHTML =

		'<font color="' + ct[0].cl + '">' + ct[0].tz + ClockString(ct[0].ct) + 

'</font>' ;

	document.all.Clock1.innerHTML =

		'<font color="' + ct[1].cl + '">' + ct[1].tz + ClockString(ct[1].ct) + 

'</font>' ;



	document.all.Clock2.innerHTML =

		'<font color="' + ct[2].cl + '">' + ct[2].tz + ClockString(ct[2].ct) + 

'</font>' ;



	document.all.Clock3.innerHTML =

		'<font color="' + ct[3].cl + '">' + ct[3].tz + ClockString(ct[3].ct) + 

'</font>' ;
	

	timerID = window.setTimeout("UpdateClocks()", 1001) ;
}



function ClockString(dt)

{

	var stemp, ampm ;
	var dt_year = dt.getUTCFullYear() ;
	var dt_month = dt.getUTCMonth() + 1 ;
	var dt_day = dt.getUTCDate() ;
	var dt_hour = dt.getUTCHours() ;
	var dt_minute = dt.getUTCMinutes() ;
	var dt_second = dt.getUTCSeconds() ;	
	dt_year = dt_year.toString() ;

	if (0 <= dt_hour && dt_hour < 24)

	{
		ampm = ' ' ;
		if (dt_hour == 0) dt_hour = 12 ;		

	} else {
		ampm = ' ' ;
		dt_hour = dt_hour - 12 ;
		if (dt_hour == 0) dt_hour = 12 ;		
	}

	if (dt_minute < 10)
		dt_minute = '0' + dt_minute ;

	if (dt_second < 10)
		dt_second = '0' + dt_second ;


	stemp = dt_month + '/' + dt_day + '/' + dt_year.substr(2,2) ;
	stemp = stemp + ' ' + dt_hour + ":" + dt_minute + ":" + dt_second + ' ' + ampm ;

	return stemp ;

}