js调用webservice中的方法实现思路及代码

webservice代码：

using System; 
using System.Web; 
using System.Collections; 
using System.Web.Services; 
using System.Web.Services.Protocols; 
using System.Web.Script.Services; 
using StoreHouse.Common; 
using StoreHouse.IDAL; 
using StoreHouse.Model; 
using System.Data.SqlClient; 
using System.Data; 
using System.Xml; 
using System.Collections.Generic; 
using System.Runtime.InteropServices; 
using System.Net.NetworkInformation; /// <summary> 
/// PageService 的摘要说明 
/// </summary> 
[WebService(Namespace = "http://tempuri.org/")] 
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)] 
[ScriptService] 
public class PageService : System.Web.Services.WebService 
{ 
ArrayList al = new ArrayList(); 
public PageService() 
{ 
//如果使用设计的组件，请取消注释以下行 
//InitializeComponent(); 
} 
/// <summary> 
/// 添加收藏 
/// </summary> 
/// <param name="fid">产品ID</param> 
/// <param name="sid">用户ID</param> 
/// <param name="flag">标识（产品收藏、企业收藏、电子样本收藏、图库收藏）</param> 
/// <returns>返回收藏状态</returns> 
[WebMethod] 
public int AddCollect(int fid,int sid,int flag) 
{ 
IProductDataProvider ipdp = ProviderManager.Create<IProductDataProvider>(); 
IEnterpriseDataProvider iedp = ProviderManager.Create<IEnterpriseDataProvider>(); 
if (flag == 1) 
{ 
ProductCollect pc = new ProductCollect(); 
pc.ProductID = fid; 
pc.UserID = sid; 
pc.AddDatetime = DateTime.Now; 
pc.UpdateDatetime = DateTime.Now; 
return ipdp.AddProductCollect(pc); 
} 
else if (flag == 2) 
{ 
EnterpriseCollect ec = new EnterpriseCollect(); 
ec.EnterpriseID = fid; 
ec.UserID = sid; 
ec.AddDatetime = DateTime.Now; 
ec.UpdateDatetime = DateTime.Now; 
return iedp.AddEnterpriseCollect(ec); 
} 
else if (flag == 3) 
{ 
EElecSampleCollect epesc = new EElecSampleCollect(); 
epesc.EElecSampleID = fid; 
epesc.UserID = sid; 
epesc.AddDatetime = DateTime.Now; 
epesc.UpdateDatetime = DateTime.Now; 
return ipdp.AddEElecSampleCollect(epesc); 
} 
else if (flag == 4) 
{ 
EPAtlasCollect epac = new EPAtlasCollect (); 
epac.EPAtlasID= fid; 
epac.UserID = sid; 
epac.AddDatetime = DateTime.Now; 
epac.UpdateDatetime = DateTime.Now; 
return ipdp.AddEPAtlasCollect(epac); 
} 
return 000000; 
}