What does this code do!!!

if (RFID.available() > 0)

client.print( “GET /te/add_data.php?”);
for (i = 0; i < 14; i++)
rfid = RFID.read();
_ Serial.print(rfid*, DEC);_
_ client.print(rfid, DEC);

Something stupid :)

Don't read many characters if you are not sure they have arrived...

That code is from a web client (browser-side) application. It is telling the web server to run the script "add_data.php", and passing it the key-value pair "serial=rfid", where rfid is, presumably, data read from an RFID reader.

Regards, Ray L.