How can I check if an app is installed from a web-page on an iPhone

As far as I know you can not, from a browser, check if an app is installed or not.

But you can try redirecting the phone to the app, and if nothing happens redirect the phone to a specified page, like this:

setTimeout(function () { window.location = "https://itunes.apple.com/appdir"; }, 25);
window.location = "appname://";

If the second line of code gives a result then the first row is never executed.

Similar questions:

iPhone browser: Checking if iPhone app is installed from browser

Is it possible to register a http+domain-based URL Scheme for iPhone apps, like YouTube and Maps?

To further the accepted answer, you sometimes need to add extra code to handle people returning to the browser after launching the app - that the setTimeout function will run whenever they do. So, I do something like this:

var now = new Date().valueOf();
setTimeout(function () {
    if (new Date().valueOf() - now > 100) return;
    window.location = "https://itunes.apple.com/appdir";
}, 25);
window.location = "appname://";

That way, if there has been a freeze in code execution (i.e., app switching), it won't run.

iOS Safari has a feature that allows you to add a "smart" banner to your webpage that will link either to your app, if it is installed, or to the App Store.

You do this by adding a meta tag to the page. You can even specify a detailed app URL if you want the app to do something special when it loads.

Details are at Apple's Promoting Apps with Smart App Banners page.

The mechanism has the advantages of being easy and presenting a standardized banner. The downside is that you don't have much control over the look or location. Also, all bets are off if the page is viewed in a browser other than Safari.

As of 2017, it seems there's no reliable way to detect an app is installed, and the redirection trick won't work everywhere.

For those like me who need to deep-link directly from emails (quite common), it is worth noting the following:

Sending emails with appScheme:// won't work fine because the links will be filtered in Gmail

Redirecting automatically to appScheme:// is blocked by Chrome: I suspect Chrome requires the redirection to be synchronous to user interaction (like a click)

You can now deep link without appScheme:// and it's better but it requires a modern platform and additional setup. Android iOS

It is worth noting that other people already thought about this in-depth. If you look at how Slack implements his "magic link" feature, you can notice that:

It sends an email with a regular HTTP link (ok with Gmail)

The web page has a big button that links to appScheme:// (ok with Chrome)

@Alistair pointed out in this answer that sometimes users will return to the browser after opening the app. A commenter to that answer indicated that the times values used had to be changed depending on iOS version.

When our team had to deal with this, we found that the time values for the initial timeout and telling whether we had returned to the browser had to be tuned, and often didn't work for all users and devices.

Rather than using an arbitrary time difference threshold to determine whether we had returned to the browser, it made sense to detect the "pagehide" and "pageshow" events.

I developed the following web page to help diagnose what was going on. It adds HTML diagnostics as the events unfold, mainly because using techniques like console logging, alerts, or Web Inspector, jsfiddle.net, etc. all had their drawbacks in this work flow. Rather than using a time threshold, the JavaScript counts the number of "pagehide" and "pageshow" events to see whether they have occurred. And I found that the most robust strategy was to use an initial timeout of 1000 (rather than the 25, 50, or 100 reported and suggested by others).

This can be served on a local server, e.g. python -m SimpleHTTPServer and viewed on iOS Safari.

To play with it, press either the "Open an installed app" or "App not installed" links. These links should cause respectively the Maps app or the App Store to open. You can then return to Safari to see the sequence and timing of the events.

(Note: this will work for Safari only. For other browsers (like Chrome) you'd have to install handlers for the pagehide/show-equivalent events).

Update: As @Mikko has pointed out in the comments, the pageshow/pagehide events we are using are apparently no longer supported in iOS8.

<html>
<head>
</head>

<body>
<a href="maps://" onclick="clickHandler()">Open an installed app</a>
<br/><br/>
<a href="xmapsx://" onclick="clickHandler()">App not installed</a>
<br/>

<script>
    var hideShowCount = 0 ;
    window.addEventListener("pagehide", function() {
        hideShowCount++;
        showEventTime('pagehide');
    });

    window.addEventListener("pageshow", function() {
        hideShowCount++;
        showEventTime('pageshow');
    });

    function clickHandler(){
        var hideShowCountAtClick = hideShowCount;
        showEventTime('click');
        setTimeout(function () {
                      showEventTime('timeout function ' + (hideShowCount-hideShowCountAtClick) + ' hide/show events');
                      if (hideShowCount == hideShowCountAtClick){
                              // app is not installed, go to App Store
                           window.location = 'http://itunes.apple.com/app';
                      }
                   }, 1000);
    }

    function currentTime()
    {
        return Date.now()/1000;
    }

    function showEventTime(event){
        var time = currentTime() ;
        document.body.appendChild(document.createElement('br'));
        document.body.appendChild(document.createTextNode(time + ' ' + event));
    }
</script>
</body>

</html>

You can check out this plugin that tries to solve the problem. It is based on the same approach as described by missemisa and Alastair etc, but uses a hidden iframe instead.

https://github.com/hampusohlsson/browser-deeplink

I needed to do something like this, and I ended up going with the following solution.

I have a specific website URL that will open a page with two buttons

Button one go to the website Button two go to the application (iPhone / Android phone / tablet). You can fall back to a default location from here if the app is not installed (like another URL or an app store) Cookie to remember the user's choice

After compiling a few answers, I've come up with the following code. What surprised me was that the timer does not get frozen on a PC (Chrome and Firefox) or Android Chrome - the trigger worked in the background, and the visibility check was the only reliable information.

var timestamp        = new Date().getTime();
var timerDelay       = 5000;
var processingBuffer = 2000;

var redirect = function(url) {
  //window.location = url;
  log('ts: ' + timestamp + '; redirecting to: ' + url);
}

var isPageHidden = function() {
    var browserSpecificProps = {hidden:1, mozHidden:1, msHidden:1, webkitHidden:1};
    for (var p in browserSpecificProps) {
        if(typeof document[p] !== "undefined"){
          return document[p];
      }
    }
    return false; // Actually inconclusive, assuming not
}
var elapsedMoreTimeThanTimerSet = function(){
  var elapsed = new Date().getTime() - timestamp;
  log('elapsed: ' + elapsed);
  return timerDelay + processingBuffer < elapsed;
}

var redirectToFallbackIfBrowserStillActive = function() {
  var elapsedMore = elapsedMoreTimeThanTimerSet();
  log('hidden:' + isPageHidden() + '; time: ' + elapsedMore);
  if (isPageHidden() || elapsedMore) {
    log('not redirecting');
  }else{
      redirect('appStoreUrl');
  }
}

var log = function(msg){
    document.getElementById('log').innerHTML += msg + "<br>";
}

setTimeout(redirectToFallbackIfBrowserStillActive, timerDelay);
redirect('nativeApp://');

JS Fiddle

The following answer still works, tested on iOS 10 through 14. It builds upon earlier answers. I added window.close() to get rid of the empty tab window that was left behind in browsers after the redirects or page return. If fixes 2 of the 4 scenarios where a blank tab would be left behind....maybe someone else can fix the 3rd & 4th

<script>
var now = new Date().valueOf();
setTimeout(function () {
  // time stamp comaprison prevents redirecting to app store a 2nd time
  if (new Date().valueOf() - now > 100) {
    window.close() ;  // scenario #4
    // old way - "return" - but this would just leave a blank page in users browser
    //return;  
  }
  if (isIOS == 1) {
    // still can't avoid the "invalid address" safari pops up
    // but at least we can explain it to users
    var msg = "'invalid address' = MyApp NOT DETECTED.\n\nREDIRECTING TO APP STORE" ;
  } else {
    var msg = "MyApp NOT DETECTED\n\nREDIRECTING TO APP STORE" ;
  }
  if (window.confirm(msg)) {
    window.location = "<?=$storeUrl?>";
    // scenario #2 - will leave a blank tab in browser
  } else {
    window.close() ;  // scenario #3
  }
}, 50);
window.location = "<?=$mobileUrl?>";  
// scenario #1 - this will leave a blank tab
</script>

I have been trying to achieve the same in a Safari extension for iOS15. It seems that all previous strategies fail - the "Open in" dialog and the "Invalid address" one are completely equal, both non-blocking, so the timer-based solutions offer inconsistent results, depending on the time it takes to load the page.

My workaround was to create an app store redirect message within a modal popup that imitates the appearance of the system prompt, hide it behind the system prompt, and dismiss it with an event listener when the tab loses focus. There are two remaining problems with the UX:

There is no way to suppress the "Invalid address" prompt. All we can do (if we don't go the Universal Links path) is to explain it afterwards with our own prompt. If the user chooses "Cancel" from the "Open in" prompt, he or she is still presented with our redirect prompt.

The following code benefitted both from the answers above and from this SO code for creating a modal popup.

// Change the following vars to suit your needs var my_app_name = "My App"; var my_app_id = "id1438151717" var my_app_scheme = "myapp://do.this" function toggleModal(isModal, inputs, elems, msg) { for (const input of inputs) input.disabled = isModal; modal.style.display = isModal ? "block" : "none"; elems[0].textContent = isModal ? msg : ""; } function myConfirm(msg) { const inputs = [...document.querySelectorAll("input, textarea, select")].filter(input => !input.disabled); const modal = document.getElementById("modal"); const elems = modal.children[0].children; return new Promise((resolve) => { toggleModal(true, inputs, elems, msg); elems[3].onclick = () => resolve(true); elems[4].onclick = () => resolve(false); }).then(result => { toggleModal(false, inputs, elems, msg); return result; }); } function redirectMessage() { var r = myConfirm("To download " + my_app_name + ", tap OK."); return r.then(ok => { if (ok) { console.log("Redirecting to the App Store..."); window.location = "itms-apps://itunes.apple.com/app/" + my_app_id; } else { console.log("User cancelled redirect to the App Store"); } return ok; }); } function prepareListener() { document.addEventListener("visibilitychange", function() { const inputs = [...document.querySelectorAll("input, textarea, select")].filter(input => !input.disabled); const modal = document.getElementById("modal"); const elems = modal.children[0].children; if (!document.hasFocus()) { console.log("User left tab. Closing modal popup") toggleModal(false, inputs, elems, ""); } }); } function onTap() { setTimeout(function() { // We can't avoid the "invalid address" Safari popup, // but at least we can explain it to users. // We will create a modal popup behind it, which the // event listener will close automatically if the app // opens and we leave the tab redirectMessage() }, 50); window.location = my_app_scheme; } prepareListener() #modal { display: none; position: fixed; z-index: 1; left: 0; top: 0; width: 100%; height: 100%; overflow: auto; background: rgb(0, 0, 0); background: rgba(0, 0, 0, 0.4); font-family: "ms sans serif", arial, sans-serif; font-size: medium; border-radius: 15px; } #modal>div { position: relative; padding: 10px; width: 320px; height: 60px; margin: 0 auto; top: 50%; margin-top: -45px; background: white; border: 2px outset; border-radius: 15px; } #cancel_button { position: fixed; right: 50%; margin-right: -95px; bottom: 50%; margin-bottom: -32px; padding: 0; border: none; background: none; color: rgb(0, 122, 255); font-size: medium; font-weight: normal; } #ok_button { position: fixed; right: 50%; margin-right: -140px; bottom: 50%; margin-bottom: -32px; padding: 0; border: none; background: none; color: rgb(0, 122, 255); font-size: medium; font-weight: semi-bold; }

Tap here to open app

The date solution is much better than others. I had to increment the time to 50 like that.

This is a Twitter example:

// On click of your event handler...
var twMessage = "Your Message to share";
var now = new Date().valueOf();
setTimeout(function () {
   if (new Date().valueOf() - now > 100) 
       return;
   var twitterUrl = "https://twitter.com/share?text=" + twMessage;
   window.open(twitterUrl, '_blank');
}, 50);
window.location = "twitter://post?message=" + twMessage;

The only problem on mobile iOS Safari is when you don't have the app installed on the device, and so Safari shows an alert that autodismisses when the new URL is opened. Anyway, it is a good solution for now!

I didn't read all of these answers, but you may be use an iframe and adding the source to, "my app://whatever".

Then check regularly on a set interval of the page is 404 or not.

You could also use an Ajax call. If there is a 404 response then the app is not installed.