checks all checkboxes in the DataTable including hidden rows

Question

I'm trying to make a function that checks all checkboxes in the DataTable, including hidden rows. Here's the html code for the "checkbox" column:

<div class="usersTable" id="userTable">
    <table cellpadding="0" cellspacing="0" id="customersList" >
        <thead>
            <tr>
                <th><input type="checkbox" name="selectall" id="selectall" class="selectall"/></th>
                <th width="200">val1</th>
                <th width="80px">val2</th>
                <th width="70px">val3</th>
                <th width="450">val4</th>
                <th width="60px">val5</th>
            </tr>
        </thead>
        <tbody>
            <tr>
                <td></td>
                <td></td>
                <td></td>
                <td></td>
                <td></td>
                <td></td>
            </tr>
        </tbody>
    </table>
</div>

Submit button:

<input type='button' value='select all' id='selectallboxes' name='selectallboxes' />

And the JQuery code that doesn't work:

$(function () {         
    otable = $('#customersList').dataTable({
        "bJQueryUI": true,
        "sPaginationType": "full_numbers",
        "aLengthMenu" : [ [10,20,50,100,1000], [10,20,50,100,1000] ],
        "iDisplayLength": 100,
        "bProcessing": true,
        "bServerSide": true,
        "aaSorting":[],         
        "iDisplayStart": 0,
        "sAjaxSource": "filename",
        ....

$("#selectallboxes").click ( function () {
        alert(dt.fnGetNodes().length + ' is total number')
        var selected = new Array();
        $('input', dt.fnGetNodes()).each( function() {
                $(this).attr('checked','checked');
                selected.push($(this).val());                       
        } );
         // convert to a string
        var mystring = selected.length;
        alert(mystring);
})

Answer 1

Try:

$("#selectallboxes").click(function () {
    var selected = new Array();
    $(otable.fnGetNodes()).find(':checkbox').each(function () {
        $this = $(this);
        $this.attr('checked', 'checked');
        selected.push($this.val());
    });
    // convert to a string
    var mystring = selected.join();
    alert(mystring);
});

.length gives you the length of the array. I've used join() to join the array into a string. DataTable's .fnGetNodes() gives you all the rows in the table including hidden ones.