问题
How exactly does adding a random number to the end of an AJAX server call prevent the database server or browser (not entirely sure which one is intended) from caching? why does this work?
回答1:
It is intended to prevent client-side (or reverse proxy) caching.
Since the cache will be keyed on the exact request, by adding a random element to the request, the exact request URL should never be seen twice; so it won't be used more than once, and an intelligent cache won't bother keeping around something that's never been seen more than once, at least, not for long.
回答2:
It's to prevent your browser (and to a reasonable amount, a web proxy) from caching requests. Typically, a query parameter - like ?rand2024= tells the browser/proxy to send the onward request with a parameter telling your application to behave differently. That's why such requests are useful to bust caches.
回答3:
Your browser caches the web page keyed by the exact text of the URL, so adding a random-number parameter ensures that the URL is different every time - thus no real caching. Your browser doesn't know that the server is (hopefully) ignoring this parameter.
来源：https://stackoverflow.com/questions/11106621/how-does-adding-a-random-number-to-the-end-of-an-ajax-server-request-prevent-cac