Floating div in ASP web form project

I am working with an ASP web form project that has a master page. I need a javascript that will provide a floating div function. The goal is to have a div within one or more of the content pages that will stay in the same position as the user scrolls down the page, using javascript. I have tried putting the function in the master page, but I keep getting errors. So I would rather have someone do this for me. Should be pretty quick and easy. I will not be providing any cpanel access because this project is just on my local machine in Visual Studio. I just need a working example of this scenario.