It can be a situation where you got a array of data that should be sent in the JSON format to server via ajax, then you can do the following <script type="text/javascript" > groups = ['A', 'B', 'C']; users = ['user1', 'user2', 'user3']; //required format is [{"group_name" : "A", "leader" : "user1"}, {"group_name" : "B", "leader" : "user2"}, {"group_name" : "C", "leader" : "user3"}] group_leaders = new Array(); len = groups.length; for(var i = 0; i < len; i++ ){ group_leaders.push({"group_name" : groups[i], "leader" : users[i]}); } alert(JSON.stringify(group_leaders)); </script> Here you can test here http://jsfiddle.net/sailesh/6wXdY/