serializing json jquery

i need an vigilant . i'm controlling . there "standard" proceed this?

my specific situation: i have an array tangible shown below:

var countries = new array();
countries[0] = 'ga';
countries[1] = 'cd';
...

and i need spin twine pass this:

$.ajax({
    type: "post",
    url: "concessions.aspx/getconcessions",
    data: "{'countries':['ga','cd']}",
...