web3-provider-with-fallback-for-old-version.js

// web3 provider with fallback for old version

window.addEventListener('load', async () => {
    // New web3 provider
    if (window.ethereum) {
        window.web3 = new Web3(ethereum);
        try {
            // ask user for permission
            await ethereum.enable();
            // user approved permission
        } catch (error) {
            // user rejected permission
        }
    }
    // Old web3 provider
    else if (window.web3) {
        window.web3 = new Web3(web3.currentProvider);
        // no need to ask for permission
    }
    // No web3 provider
    else {
        console.log('No web3 provider detected');
    }
});