How to Pass javascript variable to controller (c#) MVC

Question

ASP.Net MVC -Script to controller : How to pass variable....?

 

 

View: Textbox value moved into script(textfield==field1)

  Script:

 

Now i have to move javascript variable to controller (c#) 

 

Controller:

 POno always shows null here, how to get POno value from script...?-