jQuery datepicker- 2 inputs/textboxes and restricting range

Question

I am using the jQuery Datepicker widget with two input boxes, one for the "From" date and the second with the "To" date. I am using the jQuery Datepicker functional demo as a basis for getting the two input boxes to work with each other, but I need to be able to add these additional restrictions:

1. Date range can be no earlier than 01 December 2008

2. "To" date can be no later than today

3. Once a "From" date is selected, the "To" date can only be within a range of 7 days after the "From" date

4. If a "To" date is selected first, then the "From" date can only be within the range of 7 days before the "To" date (with the limit of 01 December being the first selectable date)

I can't seem to get all of the above working together.

In summary, I would like to be able to select a range of up to 7 days between 01 December and today (I realise I am posting this on 1st December so will only get today for the moment).

My code so far

$(function () {

$('#txtStartDate, #txtEndDate').datepicker(
            {
            showOn: "both",
            beforeShow: customRange,
            dateFormat: "dd M yy",
            firstDay: 1, 
            changeFirstDay: false
            });
});

function customRange(input) 
{ 

return {
         minDate: (input.id == "txtStartDate" ? new Date(2008, 12 - 1, 1) : null),
         minDate: (input.id == "txtEndDate" ? $("#txtStartDate").datepicker("getDate") : null), 
         maxDate: (input.id == "txtStartDate" ? $("#txtEndDate").datepicker("getDate") : null)
       }; 
}

I'm missing the 7 day range restriction and also preventing a "To" date selection before 01 December 2008 or after today. Any help would be much appreciated, Thanks.

Answer 1

Many thanks for your help Ben, I have built upon your posts and have come up with this. It is now complete and works brilliantly!

Here's a Working Demo. Add /edit to the URL to see the code

Complete Code below-

$(function () 
{   
    $('#txtStartDate, #txtEndDate').datepicker({
        showOn: "both",
        beforeShow: customRange,
        dateFormat: "dd M yy",
        firstDay: 1, 
        changeFirstDay: false
    });

});

function customRange(input) { 
    var min = new Date(2008, 11 - 1, 1), //Set this to your absolute minimum date
        dateMin = min,
        dateMax = null,
        dayRange = 6; // Set this to the range of days you want to restrict to

    if (input.id === "txtStartDate") {
        if ($("#txtEndDate").datepicker("getDate") != null) {
            dateMax = $("#txtEndDate").datepicker("getDate");
            dateMin = $("#txtEndDate").datepicker("getDate");
            dateMin.setDate(dateMin.getDate() - dayRange);
            if (dateMin < min) {
                dateMin = min;
            }
        }
        else {
            dateMax = new Date; //Set this to your absolute maximum date
        }                      
    }
    else if (input.id === "txtEndDate") {
        dateMax = new Date; //Set this to your absolute maximum date
        if ($("#txtStartDate").datepicker("getDate") != null) {
            dateMin = $("#txtStartDate").datepicker("getDate");
            var rangeMax = new Date(dateMin.getFullYear(), dateMin.getMonth(),dateMin.getDate() + dayRange);

            if(rangeMax < dateMax) {
                dateMax = rangeMax; 
            }
        }
    }
    return {
        minDate: dateMin, 
        maxDate: dateMax
    };     
}