function convert(Units1,Units2) {

  uom1Index = Units1.fUnits.selectedIndex ;
  uom2Index = Units2.toUnits.selectedIndex ;

  Uom1 = Units1.fUnits.options[uom1Index].value ;
  Uom2 = Units2.toUnits.options[uom2Index].value ;

  with (document.multBy) {
    if ( Uom1 != "=" && Uom2 != "=") { 
       Factor =  Uom2 / Uom1 ; 
       Res.value = Res.value * Factor }
    else { 
       Factor = "0.0" ;
       Res.Value = "Por favor, seleccione unidades !!" }
    }

  with (document.convertIt) {
    fromU.value = Units1.fUnits.options[uom1Index].text ;
    toU.value = Units1.fUnits.options[uom2Index].text ;
    if ( Factor > 0.0 ) { result.value = Factor / nrUnits.value }
    else { result.value = "0.0" }
    }
  } 

if (top.location != self.location) {
        top.location = self.location
}