This is the most elegant solution I've been using for a while. It doesn't require external counter variable and it provides nice degree of encapsulation.
var urls = ['http://..', 'http://..', ..];
function ajaxRequest (urls) {
if (urls.length > 0) {
$.ajax({
method: 'GET',
url: urls.pop()
})
.done(function (result)) {
ajaxRequest(urls);
});
}
}
ajaxRequest(urls);