Omnibar is a simple Firefox add-on that combines the browser's address and search bars into one, much as Google Chrome does. Although Omnibar does succeed in this task, its other promised features don't pan out.

Integrates location bar and search bar into one. Shows search and url suggestions. Quickly switch search engine using search keywords. Provides different auto-complete popup styles for compact displays. One can search from location bar using search engine keywords. When using keywords, the location bar displays the intended search engine name to be searched with. fe,
y [your search query]

Suggestions are shown for search queries as well as popular urls. Provides more compact styles for autocomplete popup.

The license of this software is Freeware, you can free download and free use this browser plug-ins software.