Waiting for AJAX

If you need to transfer execution of your page to somewhere else, but want to make sure you don't have any pending (jquery) ajax calls, use the $.active variable as below:

// 
// wait for pending ajax calls to finish first
// 
var timer = setInterval(function() {
 if ($.active==0) {
  clearInterval(timer);
  window.location.assign("www.google.com");
 }
}, 500);

How to delete multiple keys in Redis

At the command prompt:

#redis-cli KEYS "some-prefix*" | xargs redis-cli DEL

where "some-prefix" is the key prefix you want to delete.