function autoTab(input, id) {
    NS4 = (document.layers) ? true : false;
    if (NS4)
        keyCode = event.which;
    else
        keyCode = event.keyCode;
    var filter = (NS4) ? [0, 8, 9] : [0, 8, 9, 16, 17, 18, 37, 38, 39, 32, 46, 20];
    if (input.value.length >= 1 && !containsElement(filter, keyCode)) {
        input.value = input.value.slice(0, 1);
        id.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;
}