A clean separation of structure and presentation allows you to give your pages a user selectable look by applying different style sheets to the same pages. For first-time visitors this script selects a default style sheet, after selecting a favorite theme its name is stored in the cookies database.
Instructions
In the Zip file you'll find the JavaScript funtion and an example page which lets you choose between two different themes.
For using the function you only have to import it into your documents and make sure a default style sheet is used for users with JavaScript disabled: