How to refresh the arduino official WiFi shield page server

Good morning,
I have a problem with the server page created by my arduino wifi shield: I want to print the value of a sensor, and it works, but I want to see the updated value without press F5... How to refresh the value from the program?

How to refresh the value from the program?

You can't. You got a request for some data from some client. You provided that data, and shredded the client information and burned the shreds. You can not push data to the client, even if you hadn't destroyed the client information.

What you CAN do is add meta tags to the page you server, telling the client to refresh automatically, every n seconds.