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@timothycarambat
Created September 18, 2021 01:22
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Easy Web3 Meta Mask Login - static HTML and Vanilla JS
<html>
<head>
<title>Web3 Metamask Login</title>
<link href="https://unpkg.com/tailwindcss@^2/dist/tailwind.min.css" rel="stylesheet">
</head>
<body class="flex w-screen h-screen justify-center items-center">
<div class="flex-col space-y-2 justify-center items-center">
<button id='loginButton' onclick="" class="mx-auto rounded-md p-2 bg-purple-500 text-white">
Login with MetaMask
</button>
<p id='userWallet' class='text-lg text-gray-600 my-2'></p>
</div>
<script>
window.userWalletAddress = null
const loginButton = document.getElementById('loginButton')
const userWallet = document.getElementById('userWallet')
function toggleButton() {
if (!window.ethereum) {
loginButton.innerText = 'MetaMask is not installed'
loginButton.classList.remove('bg-purple-500', 'text-white')
loginButton.classList.add('bg-gray-500', 'text-gray-100', 'cursor-not-allowed')
return false
}
loginButton.addEventListener('click', loginWithMetaMask)
}
async function loginWithMetaMask() {
const accounts = await window.ethereum.request({ method: 'eth_requestAccounts' })
.catch((e) => {
console.error(e.message)
return
})
if (!accounts) { return }
window.userWalletAddress = accounts[0]
userWallet.innerText = window.userWalletAddress
loginButton.innerText = 'Sign out of MetaMask'
loginButton.removeEventListener('click', loginWithMetaMask)
setTimeout(() => {
loginButton.addEventListener('click', signOutOfMetaMask)
}, 200)
}
function signOutOfMetaMask() {
window.userWalletAddress = null
userWallet.innerText = ''
loginButton.innerText = 'Sign in with MetaMask'
loginButton.removeEventListener('click', signOutOfMetaMask)
setTimeout(() => {
loginButton.addEventListener('click', loginWithMetaMask)
}, 200)
}
window.addEventListener('DOMContentLoaded', () => {
toggleButton()
});
</script>
</body>
</html>
@rafaelfernandesx
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@qkrrkgus14 In fact, neither login nor logout is secure because you can log in with any wallet just by knowing the address and configuring it directly in the console, something like
window.userWalletAddress = " 0xSOME ADDRES"; userWallet.innerText = window.userWalletAddress;
But the code used to use this to do other things is very interesting.

@JuanLuis2006
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How can I connect metamask from my web page through a button, can someone guide me please

@lmy-dawson
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I put the button in all my pages but when i connect and go to another page it still says connect.

@rafaelfernandesx
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@lmy-dawson replace this "window.userWalletAddress = ..." with this "localStorage.setItem("userWalletAddress", "wallet")"
and this "... = window.userWalletAddress" with this "localStorage.getItem("userWalletAddress")"

@alwsyoung
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same problem @dynamo-foundation got like, did some one know how to fix ?

@lmy-dawson
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Thanks very much

@DanielVera33
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@alwsyoung You have to open the server in your archive console, if you put this: python -m http.server
Then you go to chrome, firefox... etc and search localhost:8000
Its like emulate the web conection, if you think that, you are trying to conect metamask with nothing.

@WilliamLuppi
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It does not work! i can't connect metamask, nothing happends

@Swapnil15GitHub
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my task is when we click on metamask wallet button metamask extention will open ...

i am fresher i dont know how to do it please help me

@shivergard
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This is grate intro , but unsecured as hell... I just create extension that creates window. , not taking that data are added to windows params , but they are requested over script received over body (unclean playground to test it out : https://gist.github.com/shivergard/a9c0c0d18303e9b304876ded604f77f8)

is there are any secure sample around ?

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