how to retrieve data from webserver in arduino and ethernet shield

Excuse me I want to ask. The case like this I have a link on my webserver inside this link contains data in the form of numbers that can be changed according to the data yng in inputkan. What function is in use so that arduino can read the data contained in the link. For example if arduino read data 2 then the lights on. and if arduino read data 1 then the lights off Thanks.