function cdtime(container, targetdate){
	if (!document.getElementById || !document.getElementById(container)) return
	this.container=document.getElementById(container)
	this.currentTime=new Date()
	this.targetdate=new Date(targetdate)
	this.timesup=false
	this.updateTime()
}
cdtime.prototype.updateTime=function(){
	var thisobj=this
	this.currentTime.setSeconds(this.currentTime.getSeconds()+1)
	setTimeout(function(){thisobj.updateTime()}, 1000)
}
cdtime.prototype.displaycountdown=function(baseunit, functionref){
	this.baseunit=baseunit
	this.formatresults=functionref
	this.showresults()
}
cdtime.prototype.showresults=function(){
	var thisobj=this
	var timediff=(this.targetdate-this.currentTime)/1000
	if (timediff<0){
		this.timesup=true
		this.container.innerHTML=this.formatresults()
		return
	}
	var oneMinute=60
	var oneHour=60*60
	var oneDay=60*60*24
	var dayfield=Math.floor(timediff/oneDay)
	var hourfield=Math.floor((timediff-dayfield*oneDay)/oneHour)
	var minutefield=Math.floor((timediff-dayfield*oneDay-hourfield*oneHour)/oneMinute)
	var secondfield=Math.floor((timediff-dayfield*oneDay-hourfield*oneHour-minutefield*oneMinute))
	if (this.baseunit=="hours"){
		hourfield=dayfield*24+hourfield
		dayfield="n/a"
	}
	else if (this.baseunit=="minutes"){
		minutefield=dayfield*24*60+hourfield*60+minutefield
		dayfield=hourfield="n/a"
	}
	else if (this.baseunit=="seconds"){
		var secondfield=timediff
		dayfield=hourfield=minutefield="n/a"
	}
	this.container.innerHTML=this.formatresults(dayfield, hourfield, minutefield, secondfield)
	setTimeout(function(){thisobj.showresults()}, 1000)
}
function formatresults(){
	if (this.timesup==false){
		var displaystring=""+arguments[0]+" dní "+arguments[1]+" hodín "+arguments[2]+" minút "+arguments[3]+" sekúnd"
	}
	else{
		var displaystring="Čas uplynul!"
	}
	return displaystring
}