Example to delegate your Compound Governance voting rights on the Ropsten network using web3. https://github.com/compound-developers/compound-governance-examples

delegate.js

compAbi = window.compAbi;
comp = new web3.eth.Contract(compAbi, compAddress);

let currentDelegate;
try {
  currentDelegate = await comp.methods.delegates(myAccount).call();
} catch (e) {
  currentDelegate = 0;
}

delegate.innerText = currentDelegate == 0 ? 'None' : currentDelegate;

submit.onclick = async () => {
  const delegateTo = newDelegate.value;

  if (!delegateTo) {
    alert('Invalid address to delegate your votes.');
    return;
  }

  loader.classList.remove('hidden');
  try {
    const tx = await comp.methods.delegate(delegateTo).send({ from: myAccount });
    console.log(tx);
    alert(`Successfully Delagated to ${delegateTo}`);
    window.location.reload();
  } catch(e) {
    console.error(e);
    alert(e.message);
  }
  loader.classList.add('hidden');
};