Why can't 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.js, respectively.
1.php content is as follows


$i =//A series of operations on variable i

Include ("2.php")



2.php content is as follows
echo $i;

Ajax.js general content is as follows:


Request the return content of 2.php every 1 seconds;
Httpxml.open ("Get", "2.php");
Xx.innerhtml=httpxml.responsetext;


But now the problem is that xx.innerhtml is always the same, and I don't know why?


The following information has been confirmed:
1, the $i content of 1.php in the moment changes
2, Ajax.js also follow the specified frequency to perform the request action Ajax php

------Solution--------------------
In addition to Seeeion, can you use other sharing methods to pass data?

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