I use this at work on a daily basis. This splits the content area of the browser window as you wish. It will help you in various cases. For example, to compare multiple webpages, to register domains and provision new VPS servers without without having to switch back and forth to copy/paste the customer’s information, etc.
There is some ways to split window.
* Choose the “Split Browser to” menu in the context menu.
* Choose the “Load in Split Browser” menu in the context menu on link.
* Click popup-button on top/bottom/left/right edges of the content area.
* Drop links, bookmarks, tabs, etc. to popup-button on top/bottom/left/right edges of the content area while dragging.
You can split browser infinitely, as many as your RAM and your screen allow. Enjoy split and split to your heart’s content!
Drag and drop is available to load links, bookmarks, and so on, into split browser. If you drag the toolbar of split browser, you can load the page in another split browser.
Split browsers can be closed by their closebox. “File” > “Close All Split Browser” closes all of them at once.
Status of split browsers are saved, and automatically restored on the next startup.
To install, save the add-on .xpi file to your local computer and drag into any Firefox window. For more information, please visit the developer’s website: here.
https://addons.mozilla.org/en-US/firefox/addon/4287?src=api