A container for holding information about a panedwindow widget. A panedwindow is built as a
<div>
element. Every adding of a pane adds two
<div>
elements, one for the sash, and one for the pane.
The sash element knows about the 2 surrounding
<div>
elements and changes their sizes when dragging the sash. When more than one sash element exist, the second sash element is also moved, when the first one reaches that and the pane before or after that second sash element (depending on the direction of the moving) is also changed in size. Two sash elements can touch each other that means the pane in between has size 0. And all the sashes can be moved to the left or right or to the bottom or top border. The -side option when adding a pane determines – as with the pack command – how the panes are arranged.
(Part of Tk Widgets in Javascript Paper)