Super wielkie dzięki. Sam zrobiłem to troszkę po dłuższemu

<input type="text" size="11" name="wstecz">
var czas=new Date()
var hours=czas.getHours()
var minutes=czas.getMinutes()
var seconds=czas.getSeconds()
function czas_wstecz(){
for(i=1;i<2;i++){
seconds--;
if (seconds=="-1"){
seconds=59;
minutes--;
}
if (minutes=="-1"){
minutes=59;
hours--;
}
if (hours=="-1"){
hours=23;
}
}
if ((hours<=9) && (minutes<=9) && (seconds<=9)){
document.zegarek.wstecz.value="0"+hours+":0"+minutes+":0"+seconds
}else if ((hours<=9) && (minutes<=9)){
document.zegarek.wstecz.value="0"+hours+":0"+minutes+":"+seconds
}else if ((hours<=9) && (seconds<=9)){
document.zegarek.wstecz.value="0"+hours+":"+minutes+":0"+seconds
}else if ((minutes<=9) && (seconds<=9)){
document.zegarek.wstecz.value=hours+":0"+minutes+":0"+seconds
}else if (hours<=9){
document.zegarek.wstecz.value="0"+hours+":"+minutes+":"+seconds
}else if (minutes<=9){
document.zegarek.wstecz.value=hours+":0"+minutes+":"+seconds
}else if (seconds<=9){
document.zegarek.wstecz.value=hours+":"+minutes+":0"+seconds
}else{
document.zegarek.wstecz.value=hours+":"+minutes+":"+seconds
}
setTimeout("czas_wstecz()", 1000);
}
czas_wstecz()