PHP script installation progress steps?

Some scripts don't have javascript to refresh the page itself but when they are performing step by step installation, they can auto push new texts / steps / instruct开发者_如何转开发ions to the web page.

How do they do this?

It's not entirely clear to me from your question what you mean (or pretty broad), this depends on how this was done, so a concrete example would be useful.

Anyway, normally this is done by creating an installer session and then submitting forms to a controller which will handle the input and decide upon the input and the current session's state what to display next.