I have a form built in HTML that looks like:

```
<!DOCTYPE html>
<html>
<head>
    <script type="text/javascript">
        function previousWeek() {
            var dateStr = document.getElementById("my_date").value;
            var date = new Date(dateStr);
            var datePreviousWeek = new Date(date.getFullYear(), date.getMonth(), date.getUTCDate() - 7);
            document.getElementById("my_date").value = datePreviousWeek.toISOString().slice(0, 10);
        }

        function nextWeek() {
            var dateStr = document.getElementById("my_date").value;
            var date = new Date(dateStr);
            var datePreviousWeek = new Date(date.getFullYear(), date.getMonth(), date.getUTCDate() + 7);
            document.getElementById("my_date").value = datePreviousWeek.toISOString().slice(0, 10);
        }
    </script>
    <style>
        .table {
            display: table;
        }
        .row {
            display: table-row;
        }
        .cell {
            display: table-cell;
        }
    </style>
</head>
<body>
<p>Availability Form</p>
<button onclick="previousWeek()">Previous Week</button>
<input type="date" id="my_date" />    
<script type="text/javascript">
    var now = new Date();
    var daysUntilNextMonday = 7 - now.getDay() + 1;
    var nextMonday = new Date(now.getFullYear(), now.getMonth(), now.getDate() + daysUntilNextMonday);
    document.getElementById("my_date").value = nextMonday.toISOString().slice(0, 10);
</script>
<button onclick="nextWeek()">Next Week</button>
    <form action="https://script.google.com/macros/s/AKfycbwVQja_SD4DTraHTWKH3rH81bveoIOB38U8PiSqiog/dev" method="post">
        <div class="row">
            <label>Email:</label>
            <input type="text" name="email" />
        </div>  
        <div class="row">
            <label>First Name:</label>
            <input type="text" name="firstName" />
        </div>
        <div class="row">
            <label>Last Name:</label>
            <input type="text" name="lastName" />
        </div>
        <div class="row">
            <div class="table">
                <div class="row">
                    <div class="cell">Available</div>
                    <div class="cell">Unavailable</div>
                </div>
                <div class="row">
                    <div class="cell">
                        <input type="radio" name="monday" value="available"/>
                    </div>
                    <div class="cell">
                        <input type="radio" name="monday" value="unavailable"/>
                    </div>
                </div>
                <div class="row">
                    <div class="cell">
                        <input type="radio" name="tuesday" value="available"/>
                    </div>
                    <div class="cell">
                        <input type="radio" name="tuesday" value="unavailable"/>
                    </div>
                </div>
                <div class="row">
                    <div class="cell">
                        <input type="radio" name="wednesday" value="available"/>
                    </div>
                    <div class="cell">
                        <input type="radio" name="wednesday" value="unavailable"/>
                    </div>
                </div>
                <div class="row">
                    <div class="cell">
                        <input type="radio" name="thursday" value="available"/>
                    </div>
                    <div class="cell">
                        <input type="radio" name="thursday" value="unavailable"/>
                    </div>
                </div>
                <div class="row">
                    <div class="cell">
                        <input type="radio" name="friday" value="available"/>
                    </div>
                    <div class="cell">
                        <input type="radio" name="friday" value="unavailable"/>
                    </div>
                </div>
            </div>
        </div>
        <div class="row">
            <input type="submit" value="Send" />
        </div>
    </form>

</body>
</html>

```

The issue is when the user hits the 'Next week' or 'Previous Week' buttons I need to clear out the current radio button selection (not a big issue). However, when they go back to a week that they've already entered, I need to remember what they've already entered. Additionally I need to send ALL data (not just the displayed week) in a POST request to my REST API.

I cannot find a clean way to remember this data without POSTing it to the server when the user changes weeks (which I don't want to do).

Thanks!