Sometimes I need to use a (normally Windows) computer without mouse control. Most web controls I see are accessible through basic keyboard shortcuts. Some, however can not be accessed using Tab, Space or Return.
Some basic examples are the 'Post Your Question' button on Stackexchange websites, or the 'Load More' button on the bottom of Instagram's web viewer page.
What is the fastest way to click on such a link in Firefox under these conditions?
An out-of-the-box solution is preferred since one with an addon would require installing it on every new system.