What I want to do is to let my users select multiple rows in a table and them hit a button to send this data back. My JS script file looks has the following:
<script>
$(document).ready(function () {
// Setup - add a text input to each footer cell
$('#example tfoot th').each(function () {
    var title = $(this).text();
    $(this).html('<input type="text" placeholder="Search ' + title + '" />');
});
$('#example tbody').on('click', 'tr', function () {
    $(this).toggleClass('selected');
});
$('#button').click(function () {
    alert(table.rows('.selected').data().length + ' row(s) selected');
});
// DataTable
var table = $('#example').DataTable({
    initComplete: function () {
        // Apply the search
        this.api()
            .columns()
            .every(function () {
                var that = this;
                $('input', this.footer()).on('keyup change clear', function () {
                    if (that.search() !== this.value) {
                        that.search(this.value).draw();
                    }
                });
            });
    },
});
});
</script>
My HTML code is as follows:
<form action="/get1" method="POST" name = 'input'>
<button id="button">Row count</button>
<table id="example" class="table table-striped">
    <thead>
        <tr>
            <th scope="col">Index</th>
            <th scope="col">Col2</th>
            <th scope="col">Col3</th>
            <th scope="col">Col4</th>
        </tr>
    </thead>
    <tbody>
     {% for item in rows %}
            <tr>
                <td>{{item[0]}}</td>
                <td>{{ item[1] }}</td>
                <td>{{ item[2] }}</td>
                <td>{{ item[3] }}</td>
            </tr>
        {% endfor %}
    </tbody>
<tfoot>
<tr>
                <th>Index</th>
                <th>Col2</th>
                <th>Col3</th>
                <th>Col4</th>
            </tr>
</tfoot>
  </table>
</form>
I need some help with JS and HTML to POST values (such as row index) to the backend that the backend can read.