Compare and Show Original icons missing?

[SuperTuscan]

I’m using the web-based version of Lightroom on a Mac (the LR application, not through a browser). I noticed in watcing online tutorials the Compare icons on the left-hand panel and the Show Original icon in the upper panel (see attached image). I don’t see those in my version — how can I enable or add them to my panels?

[kglad]

you probably can't 

[SuperTuscan]

@kglad can you explain? What do you mean by I 'probably can't?'  

[kglad]

1.  lr web runs in a browser.