In Opera you can simply type in opera:webdatabases
in the address field and delete all the web SQL databases stored on your computer.
How do you do the sam
On OS X 10.10.2 and Firefox 36.0.1, I deleted
~/Library/Application Support/Firefox/Profiles/*.default/storage/default/<url>/idb
In firefox, indexeddb can be deleted by:
Ctrl + Shift (Alt) + Delete
and choosing to clear offline website data.~/.mozilla/firefox/<profile>.default/storage/persistent/<website>
It appears to have been moved down a directory or two. Instead of
C:\Users\\AppData\Roaming\Mozilla\Firefox\Profiles\<*>.default\indexedDB
try
C:\Users\\AppData\Roaming\Mozilla\Firefox\Profiles\<*>.default\storage\persistent\<site>