bool flag=true;
                DataTable source=ds2.Tables[0];
                for(int i=0;i<source.Rows.Count;i++)
                {
                    double salePrice=Convert.ToDouble(source.Rows[i][9].ToString());
                    double costPrice=Convert.ToDouble(source.Rows[i][8].ToString());
                    double rate=salePrice/costPrice;

                    if(rate<1||rate>99)
                    {
                        flag=false;
                        break;
                    }
                }
                if(flag==false)
                {
                    Response.Write("<script language=jscript>alert('asdfasdf')</script>");
                }

Response.Write("<script language=jscript>alert('asdfasdf')</script>");
Response.End();

------解决方案--------------------
C# code

if(flag==false)
                {
                    Response.Write("<script language=jscript>alert('asdfasdf')</script>");
                    Response.End();//这样就执行了
                }

------解决方案--------------------
C# code

Response.Write("<script>alert('asdfasdf')</script>");
Response.End();