title: PHP - How would you make buildings or such things finish etc?
body: <p>So as you know in some browser-games such as Travian, Tribalwars and etcetera, you can build up a building, it takes X amount of time and it finishes.
  So I'm curious how that is done?</p>
  
  <p>Is it a cron-job running every second or what? How are they then doing with troops, they can't have a cron-job running ever millisecond, that wouldn't be resource usage friendly, right?</p>
  
  <p>So I'm really curious about this and I have no idea so I can't really say I have tried. I have however searched around but never found anything helpful.</p>
  
  <p>Thanks.</p>