I have a single page that I need to on occasion asynchronously check the server to see if the status of the page is current (basically, Live or Offline). You will see I have
I think Nick Craver has the right response.
For the other point of the question which is you SetTimeout , you could use SetInterval() and avoid the recursive call. But in fact I would stay with a setTimeout() and add a factor on the 15000 time. set that factor as a parameter of checklive. Then you will have a check which will be delayed progressively in time. This will avoid a LOT of HTTp requests from the guy which his still on your page since 48 hours.
Chances are that most of the time users will check for new pages in a regular manner, but someone staying for a very long time on a page is maybe not really there. Here's a piece of code I had doing that stuff.
function checkLive(settings) {
(...) //HERE ajax STUFF
setTimeout(function() {
if ( (settings.reload <2000000000) && (settings.growingfactor > 1) ) {
checkLive(settings);
settings = jQuery.extend(settings,{reload:parseInt(settings.reload*settings.growingfactor,10)});
}
},settings.reload);
}