Freeze pane in a html table within a div

I came across of some code, but some only works in IE and not Firefox. It should be able to work in both browsers. Also in the page I need to use a <div style="height:100%; overflow:auto; "> before I want to create the table so that the header row is always visible. Please help

Before you can set a % height on an element, all of its ancestors must also have a height set, otherwise the browser won't know what height to take a % of.