Keyboard shortcut/hotkey

Chrome and Firefox extension support keyboard shortcut for quick save of bookmarks.

Chrome

Click "menu" and go to "More tools" -> "Extensions"

In Extensions page click on "Menu" in top left corner of the page, then "Keyboard shortcuts"

Firefox

Click "menu" and go to "Add-ons"
On "Add-ons Manager" page click "cog" icon and select "Manage Extension Shortcuts"