Avoid automatic broswer refresh if browser is offline

Question

I have a webpage that displays ads. The page refreshes based on a users input of lets say 60 minutes for example. So if there are new ads to be displayed after the hour is up, the page will refresh itself (using JavaScript) and show the new ads.

<body oncontextmenu="return false;" onload="JavaScript:timedRefresh(<?php echo $tvout_refresh; ?>);">

$tvout_refresh is 60 mins.

Now, I've run into a slight problem, if the webpage goes offline, the page will redirect to a browser's offline page (the page that says that it can't access the website) after the timer runs out (60 mins, refreshes the page).

I've seen this piece of code after a bit of search, Allowing me to detect if the browser is online or offline.

if (navigator.onLine) {
    alert('online')
} else {
    alert('offline');
}

and

window.addEventListener("offline", function(e) {
    alert("offline");
}, false);

window.addEventListener("online", function(e) {
    alert("online");
}, false);

Now, regardless if the browser is offline or online the browser will only detect it's offline when my refresh script timer runs out and refreshes the page. Is there a way to insert a script that determines the browser is offline, skips the refresh, and resets the timer and tries again in 60 more minutes, avoiding the browser offline page?

timedRefresh is defined as follows:

function timedRefresh(timeoutPeriod) {
    setTimeout("location.reload(true);", timeoutPeriod);
}

Why not just check `navigator.onLine` in your refresh script? — Pointy, Apr 14 '14 at 18:28
can you show me an example, javascript is not my strong suit, i'm slowly learning it — Outdated Computer Tech, Apr 14 '14 at 18:28
Well you've got code in your refresh script to refresh the page, right? Just put that in an `if` statement. — Pointy, Apr 14 '14 at 18:29

score 0 · Answer 1 · answered Apr 14 '14 at 18:41

Your refresh function should look like this:

function timedRefresh(timeoutPeriod) {
    function refreshIfOnline() {
      if (navigator.onLine)
        location.reload(true);
      else
        setTimeout(refreshIfOnline, timeoutPeriod);
    }

    setTimeout(refreshIfOnline, timeoutPeriod);
}

That'll add a check of the "onLine" flag. If the browser is offline, it'll sleep for another timeout period and check again.

Now, note that the "onLine" flag isn't perfect. Detecting whether a device has Internet connectivity is ultimately a tricky problem. All you can really tell is whether you can get a response back from a remote network service within some period of time. (Obviously phones know when they're in "Airplane Mode" or whatever, but that should be the sort of thing that a browser should be able to deal with deterministically.)

score -1 · Answer 2 · answered Apr 14 '14 at 18:26

-1

you can make a AJAX remote request to server with ads, and if this request is succesefull, the browser is online.

answered Apr 14 '14 at 18:26

vodolaz095

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looking for actual answers if possible of how I can accomplish this or a point in the right direction. – Outdated Computer Tech Apr 14 '14 at 18:27

Avoid automatic broswer refresh if browser is offline

2 Answers2