Formularz z autotabulatorem w JS

<!-- Start Script Example -->
<SCRIPT LANGUAGE="JavaScript">
<!-- Begin
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;
}
//  End -->
</script>
<!-- End Script Example -->

<!-- Start Script Example Visualize -->
<p>Look how the script takes you from one<br>
input field to the next without strain:</p><br>
<form>
<font>First 3 </font><input onKeyUp="return autoTab(this, 3, event);" size="4" maxlength="3">
<font>next 3 </font><input onKeyUp="return autoTab(this, 3, event);" size="4" maxlength="3">
<font>next 4 </font><input onKeyUp="return autoTab(this, 4, event);" size="5" maxlength="4"><br><br>
<font>next 3 </font><input onKeyUp="return autoTab(this, 3, event);" size="4" maxlength="3">
<font>next 3 </font><input onKeyUp="return autoTab(this, 3, event);" size="4" maxlength="3">
<font>next 4 </font><input size="5" maxlength="4">
</form>
<!-- End Script Example -->

Look how the script takes you from one
input field to the next without strain: