How do I deposit Ether to Smart Contract using Web3.js

Question

So I am creating a web application that interacts with a smart contract that I deployed on the Ropsten TestNet.

I am able to withdraw ether from the contract to my Metamask account using a withdraw function.

However I am struggling to find out the correct method to deposit ether to the Smart Contract i.e what syntax/function do I need to use. My contract is definitely Payable(), and lets me deposit ether when I view and interact with it through Etherscan.

Any help would be greatly appreciated as I am under a lot of pressure. Thanks!

Here is how I can withdraw ether... now I need a deposit function

abi = JSON.parse('[{"constant":false,"inputs":[{"name":"amount","type":"uint256"}],"name":"withdraw","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"getMyBalance","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[],"name":"deposit","outputs":[],"payable":true,"stateMutability":"payable","type":"function"}]');
var bankContract = web3.eth.contract(abi);
contractInstance = bankContract.at('TheContractAddressHere');

function withdraw() {
  contractInstance.withdraw(300000000000000000, { from: web3.eth.accounts[0]}, function(err, result){ revert(); } );
}

Answer 1

function depositFunction() {    
    contractInstance.deposit({ from: web3.eth.accounts[0], value: <amount-in-Wei>}, function(err, result){ .... } );
}