Opens an Electron app from browser or asked them to install it.

index.js

var timeout;
document.getElementById('link').addEventListener('click', function(e) {

    timeout = window.setTimeout(function() {
        alert('install app');
    }, 1000);

    window.location = "app://";

    e.preventDefault();

});

window.addEventListener('blur', function(e) {
    window.clearTimeout(timeout);
});