I'm new to programming and have a question about navigation. What are the various methods that can achieve a "First", "Previous", "Next" and "Last" navigation, as seen in article or comic based sites? (Admittedly the "First" link isn't confusing as it can stay static, but what about the others?) For example, on the 50th page, the links would appropriately lead to the 49th and 51st (if it exists, if not it would not function but would automatically become active when such a page exists. In most examples of this I see urls ending with something like ".php?id=50" but am not certain how it's achieved, with a database? Any help will be very much appreciated, thanks.