js 调用json

url = "/plus/API/";
            postData = {k:2};
            $.post(url, postData, function(result) {
                console.log(result);
                var str = JSON.parse(result);
                 alert(str["0"]["section_name"]);
                for(var i in str) {
                    if(str[i] == 0) {
                        break;
                    }
                    $("#keshi").append(
                         "<option value=‘"+str[i]["section_name"]+"‘>"+str[i]["section_name"]+"</option>"
                    );
                }
            });