Whenever I update my website by uploading a new index.html or index.php, it always takes a long time (e.g. hours or days) for that change to propagate to my browser.
Even when I hit F5, I still get the old page loaded (quite fast too), so I'm guessing that it's being cached somewhere.
The problem happens in Firefox and Chrome.
Currently I get around this by using a different access URL every time (e.g. every time I make a change, I enter my URL as http://www.example.com/?a=43784 with a different random number every time.)
What's the correct solution to this problem? (For example, I can't imagine a news website would be very useful if people's computers/browsers cached the results for hours/days)