jQuery datepicker- 2 inputs/textboxes and restricting range

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
    };     
}