How to check if an app is installed from a web-page on an iPhone?

Question

I want to create a web-page, a page that will redirect an iPhone to the app-store if the iPhone does not have the application installed, but if the iPhone has the app instal

Answer 1

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.