Here is a 3-column layout using nested splitters. The left and right columns are a semi-fixed width; the center column grows or shrinks. Page scroll bars have been removed since all the content is inside the splitter, and the splitter is anchored to the bottom of the window using an onresize event handler.
This is the left pane of the 3-column splitter. It has been limited to a range of 100 to 250 pixels wide by inline styles. It starts at 150 pixels wide.
This is the center part of the 3-column splitter. It does most of the resizing because the left and right panes were given initial sizes and limits. Try resizing the browser window or moving a splitbar to see what I mean.
The splitbars are keyboard-accessible. Use Alt-Shift-L to select the left vertical splitbar, or Alt-Shift-R for the right one. (Or, press tab until the splitbar you want to move is in focus.) Then use the arrow keys to move the bar.
Splitters nested one or two levels deep are a great solution for user interfaces that just need a small number of user-resizable panes. If the data is more tabular in nature, it would be better to build a plugin that accepted a table as input and created resizable columns.
This is the right pane of the 3-column splitter. It has been limited to a range of 100 to 250 pixels wide by inline styles. It starts at 150 pixels wide.