Works ok for me:
$('a.popup-ajax').popover({
"html": true,
"content": function(){
var div_id = "tmp-id-" + $.now();
return details_in_popup($(this).attr('href'), div_id);
}
});
function details_in_popup(link, div_id){
$.ajax({
url: link,
success: function(response){
$('#'+div_id).html(response);
}
});
return '<div id="'+ div_id +'">Loading...</div>';
}