You have three similar options to complete this task, you can use hidden elements which will cycle through when the link is clicked. You can use ajax and load the content from the server when the link is clicked, or you can just simply change the actual content of the container of the text.

The best option really depends on your taste and the actual specifications that you're in need of.

I'd personally look into getting a light weight javascript framework. Many such as jquery will give you examples to use and you can easily implement what you need to accomplish.