This is a very simple question.
How can I indicate the cytoscape as a source via a url?
I know with D3
it is very simple
The term you're looking for is a CDN-hosted copy of the code; strictly speaking, you're still using a URL even when you specify a local copy.
It looks like Cloudflare (a major CDN company) hosts copies of the code; a google search turned up this index which should help you find the correct links for the version you need.