If en countdown

[alejandromaringomez]

Hola amigos ,
Tengo este código que es un coutdown y no sé como ponerle un if que muestre el countdown, pero en caso de que se supere la fecha limitada muestre un mensaje...

Código:

<script type="text/javascript">';
					echo '					function DaysHMSCounter(initDate, id){
												this.counterDate = new Date(initDate);
												this.container = document.getElementById(id);
												this.update();
											}
											DaysHMSCounter.prototype.calculateUnit=function(secDiff, unitSeconds){
												var tmp = Math.abs((tmp = secDiff/unitSeconds)) < 1? 0 : tmp;
												return Math.abs(tmp < 0 ? Math.ceil(tmp) : Math.floor(tmp));
											}
											DaysHMSCounter.prototype.calculate=function(){
												var secDiff = Math.abs(Math.round(((new Date()) - this.counterDate)/1000));
												this.days = this.calculateUnit(secDiff,86400);
												this.hours = this.calculateUnit((secDiff-(this.days*86400)),3600);
												this.mins = this.calculateUnit((secDiff-(this.days*86400)-(this.hours*3600)),60);
												this.secs = this.calculateUnit((secDiff-(this.days*86400)-(this.hours*3600)-(this.mins*60)),1);
											}
											DaysHMSCounter.prototype.update=function(){
												this.calculate();
												this.container.innerHTML = "<strong>" + this.days + "</strong> " + (this.days == 1? "D&iacute;a" : "D&iacute;as") + " <strong>" + this.hours + "</strong> " + (this.hours == 1? "Hora" : "Horas") + " <strong>" + this.mins + "</strong> " + (this.mins == 1? "Minuto" : "Minutos") + " <strong>" + this.secs + "</strong> " + (this.secs == 1? "Segundo" : "Segundos");
												var self = this;
												setTimeout(function(){self.update();}, (1000));
											} 
											window.onload=function(){ new DaysHMSCounter("' . $mes_ingles . ' ' . $baneo['dia_desbaneo'] . ', ' . $baneo['ano_desbaneo'] . ' ' . $baneo['hora_desbaneo'] . ':' . $baneo['minutos_desbaneo'] . ':' . $baneo['segundos_desbaneo'] . '", "counter"); }';
					echo '				</script>';