Client-side rendering (CSR)
Client-side rendering builds the page in the browser from a near-empty HTML shell and scripts. Flexible for applications, it penalizes content sites: slower perceived performance, limited crawlers, script dependency.
In practice
The test is simple: cut JavaScript and see what remains. For a business application behind a login, it barely matters; for a site that lives by its visibility, a blank screen is a design failure. The group rule: content travels as HTML; script is only an enhancer.