"Error: Provider not set or invalid" When accessing contract methods

Question

I have write a contract and deployed it through remix-ethereum IDE. That process goes alright. While accessing functions of contract through web3 in javascript I get following error Error: Provider not set or invalid"

It is noted that in the console the first address comes through following code console.log(web3.eth.defaultAccount)

Complete Code.

let web3 = new Web3(Web3.currentProvider)  
async function contract() {

    accounts = await ethereum.request({ method: 'eth_requestAccounts' });
    web3.eth.defaultAccount = accounts[0] 
    console.log(web3.eth.defaultAccount)
    var toAddress = "0x88c24A263802547F882A7F9cA0Ef58980Fe9f6f2"
    var accountAddress = '0x4a2499F46e00C25d6AFA7CC1cfa47cd69538aE61'
    var abi = [
        {
            "inputs": [
                {
                    "internalType": "uint256",
                    "name": "a",
                    "type": "uint256"
                }
            ],
            "name": "getValue",
            "outputs": [],
            "stateMutability": "nonpayable",
            "type": "function"
        },
        {
            "inputs": [],
            "name": "showValue",
            "outputs": [
                {
                    "internalType": "uint256",
                    "name": "",
                    "type": "uint256"
                }
            ],
            "stateMutability": "view",
            "type": "function"
        }
    ]
    var contractAddress ="0x3A4026a2613bAa8853e6fF29600f57cF5A9f9Ba1";
    var sampleContract = await new web3.eth.Contract(abi, contractAddress)
    console.log(sampleContract.options.address)
    sampleContract.methods.getValue(1).send({
        from: web3.eth.defaultAccount, // default from address
        gasPrice: '20000000000' // default gas price in wei, 20 gwei in this case
    })
    sampleContract.methods.showValue().call(function(error,result) {
        console.log(error)
        console.log(result)
    })
}

contract()

Answer 1

With the latest changes use window.ethereum as provider after the user has granted permission

async function contract() {
    const accounts = await window.ethereum.request({ method: 'eth_requestAccounts' });
    const web3 = new Web3(window.ethereum);