bajcmartinez/smart_contract.sol

## smart_contract.sol
pragma solidity ^0.6.6;

contract CoolNumberContract {
    uint public coolNumber = 10;

    function setCoolNumber(uint _coolNumber) public {
        coolNumber = _coolNumber;
    }
}

## web3-demo.html
<!DOCTYPE html>
<html>

<head>
    <meta charset='utf-8'>
    <meta http-equiv='X-UA-Compatible' content='IE=edge'>
    <title>Web 3 Demo</title>
    <meta name='viewport' content='width=device-width, initial-scale=1'>

    <script src='node_modules/web3/dist/web3.min.js'></script>
</head>

<body>

    Web 3 Demo
    <br >
    <button onclick="printCoolNumber();">Print Cool Number</button>
    <button onclick="changeCoolNumber();">Change Cool Number</button>
    <br /><br />
    Status: <span id="status">Loading...</span>

    <script type="text/javascript">
        async function loadWeb3() {
            if (window.ethereum) {
                window.web3 = new Web3(window.ethereum);
                window.ethereum.enable();
            }
        }

        async function loadContract() {
            return await new window.web3.eth.Contract([
                {
                    "inputs": [],
                    "name": "coolNumber",
                    "outputs": [
                        {
                            "internalType": "uint256",
                            "name": "",
                            "type": "uint256"
                        }
                    ],
                    "stateMutability": "view",
                    "type": "function"
                },
                {
                    "inputs": [
                        {
                            "internalType": "uint256",
                            "name": "_coolNumber",
                            "type": "uint256"
                        }
                    ],
                    "name": "setCoolNumber",
                    "outputs": [],
                    "stateMutability": "nonpayable",
                    "type": "function"
                }
            ], '0x5F4a8C71AFB0c01BA741106d418E78888607Ee63');
        }

        async function printCoolNumber() {
            updateStatus('fetching Cool Number...');
            const coolNumber = await window.contract.methods.coolNumber().call();
            updateStatus(`coolNumber: ${coolNumber}`);
        }

        async function getCurrentAccount() {
            const accounts = await window.web3.eth.getAccounts();
            return accounts[0];r
        }

        async function changeCoolNumber() {
            const value = Math.floor(Math.random() * 100);
            updateStatus(`Updating coolNumber with ${value}`);
            const account = await getCurrentAccount();
            const coolNumber = await window.contract.methods.setCoolNumber(value).send({ from: account });
            updateStatus('Updated.');
        }

        async function load() {
            await loadWeb3();
            window.contract = await loadContract();
            updateStatus('Ready!');
        }

        function updateStatus(status) {
            const statusEl = document.getElementById('status');
            statusEl.innerHTML = status;
            console.log(status);
        }

        load();
    </script>
</body>

</html>
	pragma solidity ^0.6.6;

	contract CoolNumberContract {
	uint public coolNumber = 10;

	function setCoolNumber(uint _coolNumber) public {
	coolNumber = _coolNumber;
	}
	}
	<!DOCTYPE html>
	<html>

	<head>
	<meta charset='utf-8'>
	<meta http-equiv='X-UA-Compatible' content='IE=edge'>
	<title>Web 3 Demo</title>
	<meta name='viewport' content='width=device-width, initial-scale=1'>

	<script src='node_modules/web3/dist/web3.min.js'></script>
	</head>

	<body>

	Web 3 Demo
	<br >
	<button onclick="printCoolNumber();">Print Cool Number</button>
	<button onclick="changeCoolNumber();">Change Cool Number</button>
	<br /><br />
	Status: <span id="status">Loading...</span>

	<script type="text/javascript">
	async function loadWeb3() {
	if (window.ethereum) {
	window.web3 = new Web3(window.ethereum);
	window.ethereum.enable();
	}
	}

	async function loadContract() {
	return await new window.web3.eth.Contract([
	{
	"inputs": [],
	"name": "coolNumber",
	"outputs": [
	{
	"internalType": "uint256",
	"name": "",
	"type": "uint256"
	}
	],
	"stateMutability": "view",
	"type": "function"
	},
	{
	"inputs": [
	{
	"internalType": "uint256",
	"name": "_coolNumber",
	"type": "uint256"
	}
	],
	"name": "setCoolNumber",
	"outputs": [],
	"stateMutability": "nonpayable",
	"type": "function"
	}
	], '0x5F4a8C71AFB0c01BA741106d418E78888607Ee63');
	}

	async function printCoolNumber() {
	updateStatus('fetching Cool Number...');
	const coolNumber = await window.contract.methods.coolNumber().call();
	updateStatus(`coolNumber: ${coolNumber}`);
	}

	async function getCurrentAccount() {
	const accounts = await window.web3.eth.getAccounts();
	return accounts[0];r
	}

	async function changeCoolNumber() {
	const value = Math.floor(Math.random() * 100);
	updateStatus(`Updating coolNumber with ${value}`);
	const account = await getCurrentAccount();
	const coolNumber = await window.contract.methods.setCoolNumber(value).send({ from: account });
	updateStatus('Updated.');
	}

	async function load() {
	await loadWeb3();
	window.contract = await loadContract();
	updateStatus('Ready!');
	}

	function updateStatus(status) {
	const statusEl = document.getElementById('status');
	statusEl.innerHTML = status;
	console.log(status);
	}

	load();
	</script>
	</body>

	</html>