Instagram Random Comment Picker

I plan to make a random comment picker website for Instagram. For instance an user wants to use these web site and s/he will paste an URL which contains comments of his/her own Instagram account and the web site will pick randomly any of them maybe one or two, maybe more.

I thought primary to get a class name (using DOM object) that contains user account name but I couldn't.

So I realized that I should use some API to get data. But surely I don't know what I have to do. If I use Graph API, can I reach to these comments (not my own Instagram accounts users' comments)?