A sidebar for Mozilla

Browsers in the Mozilla family offer a wide range of extensions. One
 of the more interesting and useful is the sidebar, called a postranní lišta in Czech. Press F9 to open it.
 It appears on the left of the browser and is essentially a frame 
 for displaying information.

Mozilla includes sidebars for history, bookmarks and search as standard. In the search sidebar 
 you can choose from several search engines, including the popular Google. 
 The information shown in a sidebar is simply HTML. It’s easy 
 to make your own sidebar and offer it on your website. There are already plenty 
 of sidebars on different subjects, from news, weather and stock-market updates
 to calculators and interactive games.

Sidebars for Czech sites and plenty of useful information 
 are available on Czilla. Instructions for building your own sidebar
 and adding it to the browser can be found in the 
 My Sidebar Developer’s Guide. Alongside
 HTML, you can use almost any of the technologies Mozilla offers, including CSS, DOM, XUL and JavaScript.