What is the difference between binding data to the Asp.net foreground and binding data to the background?

The recent project is the CPS alliance ...... Everything is OK ...... A very strange thing happened recently !!! This problem occurs two months after the test was launched: the other company said that the order was not sent back after the order was generated ???

! What's more strange is that my own computer and a colleague's computer can detect sending back.Code! (He has developed this project together before)

This is the HTML code before the accident:

The value is assigned in the background.

Public String fanlirequesturl = ""; // 51 rebate
Public String emarrequesturl = ""; // EIP

(Figure 1)

This is changed later:

(Figure 2)

The background code puts In the background code:

The first method (figure 1) is generated without bringing out the emarrequesturl value. No exceptions are found in the write log trace, but changed to the second method: put all the code implementations in the background to implement the re-sending I want. See:

I don't quite understand what is wrong with 1 or 2? And difference ???

Please enlighten me if that hero knows ...... Thank you !!!! :>