$(".db").live("change", function() {
    $(this).add($(this).next("label")).add($(this).next().next("br")).remove().insertAfter(".db:last + label + br");
    var url = "myurl.php";
    var db = [];
    $.each($('.db:checked'), function() {
    	db.push($(this).val());
    });
    if(db.length == 0) {
    	db = "none";
    }
    $.post(url, {db: db}, function(response) {
    	$("#dbdisplay").html(response);
    });
    return true;
});

<input type="checkbox" name="db[]" class="db" value="track"/><label for="track">track</label></br>
<input type="checkbox" name="db[]" class="db" value="gps"/><label for="gps">gps</label></br>
<input type="checkbox" name="db[]" class="db" value="accounting"/><label for="accounting">accounting</label></br>

$(".db").live("change", function() {
    $(this).add($(this).next("label")).add($(this).next().next("br")).remove().insertAfter(".db:last + label + br");
    var url = "myurl.php";

    var db = $('.db:checked').map(function(i,n) {
        return $(n).val();
    }).get(); //get converts it to an array

    if(db.length == 0) {
        db = "none";
    }
    $.post(url, {'db[]': db}, function(response) {
        $("#dbdisplay").html(response);
    });
    return true;
});

{'db[]': db}

$(".db").live("change", function() {
    $(this).add($(this).next("label")).add($(this).next().next("br")).remove().insertAfter(".db:last + label + br");
    var url = "myurl.php";
    var db = [];
    $.each($('.db:checked'), function() {
    	db.push($(this).val());
    });
    if(db.length == 0) {
    	db = "none";
    }
    $.post(url, {'db[]': db}, function(response) {
    	$("#dbdisplay").html(response);
    });
    return true;
});

var checkeditems = $('input:checkbox[name="review[]"]:checked')
                       .map(function() { return $(this).val() })
                       .get()
                       .join(",");
$.ajax({
    type: "POST",
    url: "/index.php/openItems/",
    data: "ids=" + checkeditems,
    success: function(msg) { $(".mainContainer").html(msg); }
});