jQuery - Post array of multiple checkbox values to php

Question

Why is only one value of the "db" checkbox values array being sent to the server side script?

JQUERY:

$(".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;
});

HTML:

<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>

Edit: I ended up answering my own question, but does anyone have documentation (or an explanation) of why this is necessary? It was difficult for me to find the exact answer (thus the posthumous post).

Answer 1

You need to have the square brackets to specify an array [] on the submitted variable name.

{'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;
});

Answer 2

I agree with @jjclarkson. Just to add, instead of pushing your ids to an array, you can use $.map:

$(".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;
});

Answer 3

$('input[name="mycheckboxes"]:checked').map(function(){ return $(this).val(); }).get().join(",");

then explode in PHP $mycheckboxes = explode(',',$_GET['mycheckboxes']);