Why cannot I get the correct file content?

Why can't I get the correct file content? I have three files: 1.php, 2. php, and Ajax. js1.php. the content is as follows & lt ;? Php & nbsp; $ I = & nbsp; // perform a series of operations on variable I include ("2.php") 2. why cannot the correct file content be obtained from php content?
I have three files: 1.php, 2. php, and Ajax. js.
1. php content is as follows


$ I = // perform a series of operations on variable I

Include ("2.php ")



2. the php content is as follows:
Echo $ I;

The content of Ajax. js is as follows:


Request the response content of 2.php every 1 second;
Httpxml. open ("get", "2.php ");
XX. innerHTML = httpxml. responseText;


But now the problem is that XX. innerHTML remains unchanged. why?


Confirm the following information:
1. The $ I content in php is constantly changing.
2. Ajax. js also executes the request action according to the specified frequency. ajax php
------ Solution --------------------
Apart from seeeion, can you use other sharing methods to transmit data?