Javascript连接数字,而不是加起来

Question

它一直将我的数字连接到2111而不是5.这是为什么？我尝试过使用parseInt但没有运气.res3 btw表示我正在执行的数据库查询.

var dt_total_hours = 0;

            dt_total_hours += res3.fieldByName(dt_cost_per_hour);
            dt_total_hours += res3.fieldByName(dt_prod_dt_hours);
            dt_total_hours += res3.fieldByName(dt_prod_rate);
            dt_total_hours += res3.fieldByName(dt_cost_per_unit);
            dt_total_hours += res3.fieldByName(dt_scrap_startup_cost);
            dt_total_hours += res3.fieldByName(dt_labor_expense);
            dt_total_hours += res3.fieldByName(dt_since_issues_first_noticed);
            dt_total_hours += res3.fieldByName(dt_wo_for_maint);
            dt_total_hours += res3.fieldByName(dt_investigation);
            dt_total_hours += res3.fieldByName(dt_maint_made_bandaid);
            dt_total_hours += res3.fieldByName(dt_parts_outsourcing);
            dt_total_hours += res3.fieldByName(dt_get_equip_out_prod);
            dt_total_hours += res3.fieldByName(dt_perm_repair);
            dt_total_hours += res3.fieldByName(dt_equip_back_to_prod);
            dt_total_hours += res3.fieldByName(dt_to_full_prod_speed);
            dt_total_hours += res3.fieldByName(dt_other);

Answer 1

如果值是字符串,则它们将被连接,而不是以数字形式添加.

尝试从字符串值构造一个数字:

dt_total_hours += Number(res3.fieldByName(dt_cost_per_hour));
//                ^------ Force a number here instead of a string.