I am building a small site for a friend who is getting married and they have their gift list online. Each gift is a node which I am thinking will have a boolean field called something like "bought". The functionality I want to create is that visitors can look at a list of gifts and, if they want to buy something for them they just need to click a button next to it.
So my question is simple, can I change the value of a node field when a user clicks a button?