vb6 webbrowser 事件捕获

Private WithEvents htmlDocument As htmlDocument
Private WithEvents btnCompute As MSHTML.HTMLButtonElement
Private WithEvents txtNum1 As MSHTML.HTMLInputTextElement
Private WithEvents txtNum2 As MSHTML.HTMLInputTextElement
Private WithEvents txtResult As MSHTML.HTMLInputTextElement

Private Function btnCompute_onclick() As Boolean
    On Error GoTo ErrHandler:
    txtResult.Value = CDbl(txtNum1.Value) + CDbl(txtNum2.Value)
    Exit Function
ErrHandler:
    MsgBox Err.Description
End Function

Private Sub Command1_Click()
    Text1.Visible = Not Text1.Visible
End Sub

Private Sub Form_Load()
    WebBrowser1.Navigate "about:blank"
    Do While WebBrowser1.Busy Or WebBrowser1.ReadyState <> READYSTATE_COMPLETE
        DoEvents
    Loop
    WebBrowser1.Document.write Text1.Text
    Do While WebBrowser1.Busy Or WebBrowser1.ReadyState <> READYSTATE_COMPLETE
        DoEvents
    Loop

    Set htmlDocument = WebBrowser1.Document
    Set btnCompute = htmlDocument.getElementById("btnCompute")
    Set txtNum1 = htmlDocument.getElementById("txtNum1")
    Set txtNum2 = htmlDocument.getElementById("txtNum2")
    Set txtResult = htmlDocument.getElementById("txtResult")

End Sub

Private Function htmlDocument_onclick() As Boolean
    Debug.Print "触发了元素" & htmlDocument.parentWindow.event.srcElement.id & "的" & htmlDocument.parentWindow.event.Type & "事件"
End Function