function PopupVolumeCalculator() {
    ddlVolumeUnitCalc.SetValue(ddlVolumeUnit.GetValue());
    popVolumeCalculator.Show();
}
function CancelVolumeCalculator() {
    popVolumeCalculator.Hide();
}
function AcceptVolumeCalculator() {
    var VolumeFlow = txtSuggestedVolumeFlow.GetText();
    var VolumeUnit = ddlVolumeUnitCalc.GetValue();
    if (isNumber(VolumeFlow)) {
        txtVolume.SetText(VolumeFlow);
        ddlVolumeUnit.SetValue(VolumeUnit);
    }
    popVolumeCalculator.Hide();    
}
function vcHeightWidthLengthChange() {
    //calculates room area from length width height
    var Height = txtHeight.GetText();
    var Width = txtWidth.GetText();
    var Length = txtLength.GetText();
    var Area;
    if (isNumber(Height) && isNumber(Width) && isNumber(Length)) {
        Area = Height * Width * Length;
        txtRoomVolume.SetText(Math.round(Area));
    } else {
        txtRoomVolume.SetText("");
    }
    vcCalculateSuggestedVolumeFlow();
}
function vcAreaRoomVolumeChange() {
    txtHeight.SetText("");
    txtWidth.SetText("");
    txtLength.SetText("");
    vcCalculateSuggestedVolumeFlow();
}
function vcAirChangesChange() {
    ddlRoomType.SetSelectedIndex(-1);
    vcCalculateSuggestedVolumeFlow();
}
function vcCalculateSuggestedVolumeFlow() {
    var SizeUnit = ddlSize.GetValue();
    var Area = txtRoomVolume.GetText();
    var AirChanges = txtAirChanges.GetText();
    var VolumeUnit = ddlVolumeUnitCalc.GetValue();

    if (isNumber(Area) && isNumber(AirChanges)) {
        if (SizeUnit == 1) {
            Area = Area / 10.7639104; //convert to m3 
        }
        var M3H = Area * AirChanges; //calculate m3/h volume flow
        //alert(changeVolumeUnit(M3H, eVolumeUnit.m3h, VolumeUnit));
        txtSuggestedVolumeFlow.SetText((Math.round(changeVolumeUnit(M3H,eVolumeUnit.m3h,VolumeUnit)*100)/100));
    } else {
        txtSuggestedVolumeFlow.SetText("");
    }
}
function vcVolumeUnitChange() {
    vcCalculateSuggestedVolumeFlow();    
}
function VolumeCalculatorUpdateAirChanges() {
    var AirChanges = ddlRoomType.GetValue();
    txtAirChanges.SetText(AirChanges);
    vcCalculateSuggestedVolumeFlow();
}
function ddlSizeChanged() {
    //txtHeight
}