INSERT INTO wp DB from input fields

I’m creating (and deleting) input fields dynamically in jQuery so they looks like:

<div id="new">
<div>
    <input type="text" name="title1" value="" />
    <input type="text" name="desc1" value="" />
</div>
<div>
    <input type="text" name="title4" value="" />
    <input type="text" name="desc4" value="" />
</div>
<div>
    <input type="text" name="title7" value="" />
    <input type="text" name="desc7" value="" />
</div>
</div>

As you can see, my fields names are not always like: 1,2,3 but they’re sometimes like 1,4,7.

My php code (part) to insert row into db table:

$i = 0;
global $wpdb;
$table_name = $wpdb->prefix . 'plugin';

$wpdb->insert( $table_name, array( 'title' => $_POST['title'], 'desc' => $_POST['desc'] ) );

jQuery:

var count = <?php echo $i; ?>;
$("#addnewbutton").click(function() {
    count = count + 1;
    $('#new').append('<div><input type="text" name="title'+count+'" value="" /><input type="text" name="desc'+count+'" value="" /></div>');
});

I know that I need to use “for” loop (probably) but I don’t know how to do it and I don’t want to add empty rows.

Regards