If you just go to Shanghai(https://www.travelchinaguide.com/cityguides/shanghai.htm) to visit your husband for a period, you can apply for Tourist Visa for family visit, it is generally valid for 3 months, single entry, 30 days stay duration. If you want to accompany your husband till the end of his work, you can apply for China Work Visa(https://www.travelchinaguide.com/embassy/visa/work.htm) as dependents. After entering China by holding the dependent visa, you can apply for temporary residence permit within 30 days at the local police station.