Waiting until a transaction is confirmed to send an email

TheWritersBlock.sol

pragma solidity ^0.4.23;

contract TheWritersBlock {
  address public owner;
  mapping (address => uint256) public balance;

  constructor() public {
    owner = msg.sender;
  }

  function kill() public {
    if(msg.sender == owner) selfdestruct(owner);
  }

  function payWriter(uint amount, address receiver) public returns (bool success) {
    if (balance[msg.sender] < amount) throw;
    balance[msg.sender] -= amount;
    receiver.transfer(amount);

    return true;
  }
}

// This contract is already deployed at 0x8ac6f809862eae42fefafcca212efb61607e13e0

transaction.js

var web3 = window.web3;

function payUser(amt, addr) {
  var contractAbi = [[{"constant": false,"inputs": [{"name": "amount","type": "uint256"},{"name": "receiver","type": "address"}],"name": "payWriter","outputs": [{"name": "success","type": "bool"}],"payable": false,"stateMutability": "nonpayable","type": "function"},{"constant": false,"inputs": [],"name": "kill","outputs": [],"payable": false,"stateMutability": "nonpayable","type": "function"},{"constant": true,"inputs": [],"name": "owner","outputs": [{"name": "","type": "address"}],"payable": false,"stateMutability": "view","type": "function"},{"constant": true,"inputs": [{"name": "","type": "address"}],"name": "balance","outputs": [{"name": "","type": "uint256"}],"payable": false,"stateMutability": "view","type": "function"},{"inputs": [],"payable": false,"stateMutability": "nonpayable","type": "constructor"}]];
  var contract = web3.eth.contract(contractAbi).at('0x8ac6f809862eae42fefafcca212efb61607e13e0');
  
  contract.payWriter(amt, addr, {from: web3.eth.accounts[0]}, funcition(err, txid) {
    if (err) { console.log(err); }
    else { monitorTransaction(txid); }
  });
}

function getTx(txid) {
  return web3.eth.getTransactionReceipt(txid);
}

function monitorTransaction(txid) {
  var timesCounted = 0;
  var confirmed = false;
  var receipt = getTx(txid);
  while (true) {
    setTimeout(getTx(txid), 1000)
    timesCounted++;
    
    if (timesCounted == 300) break;
    if (receipt['status'] == "0x1" { //Ox0 = failed, 0x1 = confirmed, I assume this will be undefined until the transaction is confirmed
      confirmed = true;
      break;
    }
    if (receipt['status'] == "0x0" break;
  }
        
  if (confirmed) {
      // send email
  }
}

TutorialDeploy.md

I used an already-deployed smart contract for this, but if you would like to be able to write and deploy your own contracts, it's better to just look at the deploying portion of this very in-depth article that I found very useful for learning.