Changing autocomplete behavior - Firefox

The Location Bar, the Search Bar and some form fields on web pages have autocomplete dropdowns that appear with a list of previously-entered data. You can disable the display of autocomplete entries by editing your configuration files as described below.

Note that this method does not actually delete the internal lists of previously entered data; it merely prevents their display. Location Bar autocomplete is an integral part of the History mechanism in Firefox: its data is stored in the history.dat file, and persists for the same duration as History items. Currently the only way to fully disable Location Bar autocomplete is to disable History. This can be done by setting the number of days of saved history to zero.

The method below has some problems. It will cause some errors appear in the JavaScript Console if you have chrome errors enabled, and in some circumstances it may cause the browser to malfunction.

In userChrome.css, add the following lines:

/* Remove autocomplete dropdown */
#PopupAutoComplete > .autocomplete-tree { display: none !important; }

If you also want to remove the dropdown button at the far right of the Location Bar, add the following line:

.autocomplete-history-dropmarker { display: none !important; }

You may also want to enable inline autocomplete.

See also

Deleting autocomplete entries