function convert() {
  var mval = document.getElementById('value').value;
  var uvalue = document.getElementById('value').value;

  var s = document.getElementById('unit1');
  var unit1 = s.options[s.selectedIndex].value;
  s = document.getElementById('unit2');
  var unit2 = document.getElementById('unit2').value;

  yksikkonimi = " p-m³"

  if (unit2 == 2) {
    yksikkonimi = " i-m³"
  }
  if (unit2 == 3) {
    yksikkonimi = " k-m³"
  }

  //pino
  if (unit1 == 1 && unit2 == 2) {
    mval = (uvalue * 1.6393442622950819672131147540984);
  }
  if (unit1 == 1 && unit2 == 3) {
    mval = (uvalue * 0.65359477124183006535947712418301);
  }
  //irto
  if (unit1 == 2 && unit2 == 1) {
    mval = (uvalue * 0.613496932515337);
  }
  if (unit1 == 2 && unit2 == 3) {
    mval = (uvalue * 0.40160642570281124497991967871486);
  }
  //kiinto
  if (unit1 == 3 && unit2 == 1) {
    mval = (uvalue * 1.53);
  }
  if (unit1 == 3 && unit2 == 2) {
    mval = (uvalue * 2.4939);
  }

  mval = Math.round(mval*Math.pow(10,2))/Math.pow(10,2);
  document.getElementById('valchresult').value = mval + yksikkonimi;
}