How to persist the states of buttons and other settings in the toolbar?

I have ckeditor on a webpage.

Just before the user closes the webpage (or navigates away from the webpage), I would like to save the state of the ckeditor's toolbar, and reload the same toolbar state when the user visits the webpage again.

Simple example:

1. User opens the webpage containing ckeditor.
2. User clicks on the buttons Bold, Italic, Underline and sets the font color to red.
3. User types his message in ckeditor and posts his message to the server.
4. User closes the browser, or navigates to some other page.
5. After a few minutes, user visits again the webpage containing ckeditor.
6. The buttons Bold, Italic, Underline are already set and the font color is already set to red.

Can somebody provide a solution how to make this work?

Thanks