Basic Ajax Cache Issue

Question

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

Answer 1

Use the cache option of $.ajax() to append a cache breaker to the URL, like this:

$.ajax({
    type: 'get',
    url: '/live/live.php',
    dataType: 'json',
    cache: false,
    //success, etc.
});

If that doesn't resolve it...look at firebug, see if a request is being made (it should be after this for sure), if it's still getting an old value, the issue is in PHP, not JavaScript.

---

Unrelated to the issue, just a side tip: If you need no parameters, you can skip the anonymous function call, this:

setTimeout(function() { checkLive() } ,15000);

can just be:

setTimeout(checkLive, 15000);

Answer 2

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);
}

Answer 3

You can check if it's a caching issue by adding unique ID to the url:

change url: '/live/live.php', to url: '/live/live.php?'+new Date().getTime(),

Cheers

G.