I have found this autoTab script on the net:
Code JavaScript:
var isNN = (navigator.appName.indexOf("Netscape")!=-1);
function autoTab(input,len, e) {
var keyCode = (isNN) ? e.which : e.keyCode; 
var filter = (isNN) ? [0,8,9] : [0,8,9,16,17,18,37,38,39,40,46];
if(input.value.length >= len && !containsElement(filter,keyCode)) {
input.value = input.value.slice(0, len);
input.form[(getIndex(input)+1) % input.form.length].focus();
}
function containsElement(arr, ele) {
var found = false, index = 0;
while(!found && index < arr.length)
if(arr[index] == ele)
found = true;
else
index++;
return found;
}
function getIndex(input) {
var index = -1, i = 0, found = false;
while (i < input.form.length && index == -1)
if (input.form[i] == input)index = i;
else i++;
return index;
}
return true;
}

And called like this:
Code HTML4Strict:
<input onKeyUp="return autoTab(this, 1, event);" size="2" maxlength="2">

Now what I want is if you type "1" in the field an aleretbox popup with 2 choices... first choice is to accept that the field should be only "1" and the second choice is to be able to change the filed 2 a 2 digit field where you can type ex. "13"...

I got this to envoke the alertbox:
Code JavaScript:
if(input.value == 1) {
alert("I only want it to be 1");
}

But I dont know how to make choices within the alertbox and if choice 2 is selected alter the field to a 2 digit field...

Please help and thanks in advance...