Detecting the Ultra Wallet

To detect if a user has already installed the Ultra Wallet browser extension the web application should run over HTTPS and check for the existence of an ultra object in the window variable.

if ('ultra' in window) {
  console.log('Ultra Wallet is installed!');
}

This code can be called when you want (for example, when clicking on a button or a link).
If you want this check to be carried out automatically when the web page loads, you will need to integrate it into the load event in the window variable:

if(document.readyState !== 'complete') {
    window.addEventListener('load',afterWindowLoaded);
} else {
    afterWindowLoaded();
}

function afterWindowLoaded(){
    if ('ultra' in window) {
        console.log('Page load: Ultra Wallet is installed!');
    } else {
        console.log('Page load: No Ultra Wallet extension detected!');
    }
}