Go to online help:

NavigateForwardCustom

There's a code example there:

Code:
Object oStatusHelper is a cWebButton
    Set piColumnSpan to 4
    Set psCaption to "Help Me Decide"
    Set piColumnIndex to 4

    Procedure OnClick
        Send NavigateForwardCustom of oZoomCustomerStatusHelp Self
        // note that using NavigateForward would work just as well in this sample
    End_Procedure
    
    Procedure OnGetNavigateForwardData tWebNavigateData NavigateData Handle hoToView
        String sValue
        Boolean bChecked
        Get GetChecked of oCustomerStatus to bChecked
        WebGet psValue of oCustomerName to sValue
        Get NamedValueAdd NavigateData.NamedValues "name" sValue to NavigateData.NamedValues
        Get NamedValueAdd NavigateData.NamedValues "status" bChecked to NavigateData.NamedValues
    End_Procedure
    
    Procedure OnNavigateBack Handle hoCallback tWebNavigateData NavigateData
        Boolean bFound bOldStat bNewStat
        String sValue
        Get NamedValueGet NavigateData.NamedValues "newstatus" to sValue
        Get GetChecked of oCustomerStatus to bOldStat
        Move (sValue="1") to bNewStat
        If (bNewStat<>bOldStat) Begin
            Send SetChecked of oCustomerStatus bNewStat
            WebSet pbChanged of oCustomerStatus to True
        End
    End_Procedure
End_Object
The above example can never work as the example code is missing a ByRef.

Eg.
Code:
Procedure OnGetNavigateForwardData tWebNavigateData NavigateData Handle hoToView
Should have been:
Code:
Procedure OnGetNavigateForwardData tWebNavigateData ByRef NavigateData Handle hoToView
--
Wil