Constant update value with request GET with gsm shield arduino

Hello erverybody. At first time I apologise for my bad english.

My main objective is recive and send date from gsm shield arduino to mysql. To do this I have to execute requests GET and POST. Well. Now I am trying execute GET request. But I have problems becouse with examples of arduino libraries or internet do only one connection. That is to say, They obtain one value of your page in your domain only once in the moment of execute code in arduino. I need do a constant resquest becouse in any moment the value of my variable can change and I want this to be instantly… Now It is my main objective. But I am thinking It’s a bad solution about a constant request becouse it this causes high latency with which It spend data gsm and energy. The ideal would be when the value change from my page atrought the internet send to gsm shiled a notice and then gsm execute request GET and POST. But it has to be without sms or call voice becouse this services spend extra money. CAN YOU HELP ME. Thankssss!!!

I want this to be instantly

Get over it. Nothing in the world of client/server communications happens instantly.

send to gsm shiled a notice

IF it is your server, make that happen. If it is not your server, forget it.

But it has to be without sms or call voice becouse this services spend extra money.

You expect your device to make GET or POST requests without costing money? What planet are you from?

What you want, is to use a GPRS data session with your modem - connecting to your 'central' servers IP. You on,y pay for data used, so design your applications to be sparse with Comms.

Then, start reading up about AJAX for near-realtime web interaction.