Javascript Timer如何用图像替换数字？

您好，如何将以下JavaScript计时器中的数字替换为相应的图片。例如，dig1.png为0，dig2.png为1，dig3为3。png ..... colon（:)和colo.png。00:23:01 == >>

var Timer;
var TotalSeconds;


function CreateTimer(TimerID, Time) {
Timer = document.getElementById(TimerID);
TotalSeconds = Time;

UpdateTimer()
window.setTimeout("Tick()", 1000);
}

function Tick() {
if (TotalSeconds <= 0) {
doSubmit();
document.getElementById("timeisup").innerHTML = "Time is up response.";
return;
}

TotalSeconds -= 1;
UpdateTimer()
window.setTimeout("Tick()", 1000);
}


function UpdateTimer() {
Timer.innerHTML = TotalSeconds;
}

function UpdateTimer() {
var Seconds = TotalSeconds;

var Days = Math.floor(Seconds / 86400);
Seconds -= Days * 86400;

var Hours = Math.floor(Seconds / 3600);
Seconds -= Hours * (3600);

var Minutes = Math.floor(Seconds / 60);
Seconds -= Minutes * (60);


var TimeStr = ((Days > 0) ? Days + " days " : "") + LeadingZero(Hours) + ":" 
+ LeadingZero(Minutes) + ":" + LeadingZero(Seconds)


Timer.innerHTML = TimeStr;
}


function LeadingZero(Time) {

return (Time < 10) ? "0" + Time : + Time;

}

这是显示计时器的html标记...

<span id="timer"style="font-weight: bold;"></span><script
type="text/javascript">window.onload = CreateTimer("timer", 7200);</script>

谢谢