how to pass a session value

Question

 how to pass a session value form one tab textbox to another tab textbox using ajax tab container

 

im using ajax tab container in tab1 username is store in session and i read a session value in tab2 textbox how i  pass the value

 

 

Session["_accessUserID"] = txt_emp_id.Text;   ///store the value in session  

 

txt_n_emp_id.Text = Session["_accessUserID"].ToString(); / And read value  and put                                                                                                code in page load error is raied