Edit in JSFiddle

function getCurrentFinancialYear() {
  var fiscalyear = "";
  var today = new Date();
  if ((today.getMonth() + 1) <= 3) {
    fiscalyear = (today.getFullYear() - 1) + "-" + today.getFullYear()
  } else {
    fiscalyear = today.getFullYear() + "-" + (today.getFullYear() + 1)
  }
  return fiscalyear
}

document.getElementById("spFY").innerHTML=getCurrentFinancialYear();

Current Financial Year :-<span id='spFY'></span>