A page jumps to another address as soon as you open it. That behaviour alone does not reveal whether the server returned an HTTP redirect or a browser script initiated the move.
Inspect the first response
Open the network panel, preserve its log and request the original URL directly. An HTTP redirect shows an appropriate 3xx status and usually a destination in the Location header. A JavaScript redirect may begin with an ordinary HTML response.
Fictional example: an old article returns 200, then its script assigns the new address to window.location. It looks similar to a server redirect in the browser, but requires additional processing.
Where possible, inspect the page with JavaScript disabled too. This helps classify the behaviour but does not replace checking the original network response.
Record why the navigation occurs
For a permanent move, an appropriate server-side redirect is generally clearer. Google’s handling of a JavaScript redirect also depends on rendering.
Not every browser navigation represents a move, however. A deliberate transition following an interaction may be part of the application. Avoid changing those flows indiscriminately.
Record the source URL, intended destination and whether the move is permanent. After correcting the setup, inspect the first response again rather than relying only on where the browser ends up.
Find meta refresh in the original HTML
Search the source for http-equiv="refresh". The fictional attribute content="5; url=/new-article/" requests a move after five seconds. Also check whether an HTTP redirect already occurred before this HTML response.
Open the declared destination separately. Relative addresses can resolve differently after a directory change. Google distinguishes immediate meta refresh from a delayed change. A suitable HTTP redirect is usually clearer for an ordinary permanent move.
A countdown followed by the homepage does not replace mapping to the relevant successor article. Establish whether important notices on the old page need transferring to the destination. After changing it, check the first response, the relevant final destination and any further hops.
Related check: Prioritise a redirect mapping.
If the responsible layer is unclear, the Technology and stack review helps assess application and deployment structure before changes.