There is some hype about DeFi and it goes basically to Ethereum
(I have not seen yet other non-Ethereum blockchain that prmote DeFi term usage).
Then there is MetaMask that is essential a wallet distributed as Chrome browser plugin.
But some blockchain site specifically require MetaMask and establish some communication between.
I know Ethereum, but it is blockchain and basically backend technology.
I think is has nothing to do with browsers and websites.
What exactly (technically speaking) is Ethereum blockchain enabled website?
Or other way round, how exactly MetaMask is to interact with website visited?
How websites interact with the MetaMask extension
Metamask extension injects the ethereum property into the JS window object. This property links to the JS API of the Metamask extension, allowing the website some level of control - such as "open a window requesting the user to submit this transaction" (but not "get the private key" for example).
This example JS code opens the Metamask window and asks the user for permission to share their (public) addresses with the website, when the myBtn is clicked. The shared addresses are then saved into the accounts variable.
$('#myBtn').click(async (e) => {
let accounts = await window.ethereum.request({
'method': 'eth_requestAccounts'
});
}
You can find more info at https://docs.metamask.io/guide/getting-started.html#getting-started