var clockTimerID = null;
var monNames = new Array ('',
		'ledna','února','března',
		'dubna','května','června',
		'července','srpna','září',
		'října','listopadu','prosince');
var dayNames = new Array ('',
		'neděle','pondělí',
		'úterý','středa',
		'čtvrtek','pátek',
		'sobota' );

function startClock () {

	if ( clockTimerID != null ) {
		clearTimeout ( clockTimerID );
	}

	update_clock_display ();
}

function update_clock_display () {

	// GET THE CURRENT SYSTEM DATE/TIME INFORMATION
	var dateNow = new Date ();

	// SPLIT THE DATE INTO VARIOUS DATE/TIME COMPONENTS
	var hour = dateNow.getHours ();
	var mins = dateNow.getMinutes ();
	var secs = dateNow.getSeconds ();
	var date = dateNow.getDate ();
	var daynum = dateNow.getDay () + 1;
	var monnum = dateNow.getMonth () + 1;
	var year = dateNow.getYear ();

	// SECONDARY CALCULATION FOR CLOCK DIGITS, ETC.
	var hour1 = Math.floor ( hour / 10 );
	var hour2 = hour % 10;
	var mins1 = Math.floor ( mins / 10 );
	var mins2 = mins % 10;
	var secs1 = Math.floor ( secs / 10 );
	var secs2 = secs % 10;
	var date1 = Math.floor (date / 10);
	var date2 = date % 10;
	if ( year < 200 ) {
		year += 1900;
	}

	// NOW START THE ROUTINES TO UPDATE THE CLOCK
	// updateDate('fullDate',monNames,date1,date2,monnum,year);
	updateTime('bigTime',hour1,hour2,mins1,mins2);
	updateDayName('dayName',dayNames,daynum,date1,date2,monnum);
	//updateSeconds('seconds',secs1,secs2);

	// THIS LINE RECURSIVELY CALLS IT'S OWN ROUTINE EVERY SECOND
	clockTimerID = setTimeout ("update_clock_display ()" ,1000)
}

var prevDate = "";
function updateDate(objId,monNames,date1,date2,monnum,year) {

	var htmstr = date1 + '' + date2 + '-' + monNames[monnum] + '-' + year;
	if (htmstr != prevDate) {
		squirtHTML(objId,htmstr);
	}
	prevDate = htmstr;
}

var prevTime = "";
function updateTime(objId,hour1,hour2,mins1,mins2) {

	var htmstr = hour1 + '' + hour2 + ':' + mins1 + '' + mins2;
	if (htmstr != prevTime) {
		squirtHTML(objId,htmstr);
	}
	prevTime = htmstr;
}

var prevDayName = "";
function updateDayName(objId,dayNames,dayNum,date1,date2,monnum) {

	var htmstr = dayNames[dayNum] + ', ' + date1 + '' + date2 + '. '+ monNames[monnum] ; 
	if (htmstr != prevDayName) {
		squirtHTML(objId,htmstr);
	}
	prevDayName = htmstr;
}

var prevSeconds = "";
function updateSeconds(objId,secs1,secs2) {

	var htmstr = secs1 + '' + secs2;
	if (htmstr != prevSeconds) {
		squirtHTML(objId,htmstr);
	}
	prevSeconds = htmstr;
}

function convertObj(objStr) {

	var objID = null;

	if (document.getElementById) {
		objID = document.getElementById(objStr);
	} else if (document.all) {
		objID = eval("document." + objStr);
	} else if (document.layers) {
		objID = eval("document.layers." + objStr);
	}

	return(objID);
}

function squirtHTML(objStr,htmstr) {

	var objID = convertObj(objStr);
	objID.innerHTML = htmstr;
}