First Time Update panel is not working

Question

Dear Sir/Ma'am

 i have two dropdown for state,cit. On the changing values of state, City gets bind. In city there is one values named others.  On Selecting it i want to display a textbox. but when i use asynchronous trigger it not working on first time after that it is working fine.  i am sending my design view code. 


Please help me.


Thanks