Here is my php code
That is not php code. It is nothing more than static html.
Where does that code live? If the Arduino is a client, making a GET request to a server to get that data, there is no way that the Arduino can render that code in a way that a user can interact with it.
If the Arduino is a server, serving up that page, then when the user interacts with the application that is rendering that data, the action method means that any interaction will generate a new GET request that the Arduino is supposed to deal with.
The question that you have tap danced around long enough is simple. Is the Arduino a client or is it a server? Post your code to show which it is.
If it is a client, I'll repeat my statement that you are going about this all wrong. You can't get data from a served client (a browser) from another client (the Arduino). It simply is not possible. The server doesn't even know which client it sent that page to, so there is no possible way to have the action method on that client send information to the Arduino as client.
The Arduino as client pulls data. The Arduino as server pushes data only in response to a pull request.