Managing Client-side Scripts in the IDE

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Introduction

Managing client-side VBScripts is often necessary in some projects. Here is a solution how to do it. All VBScripts are held in a special project folder. The script is loaded into a hidden textbox and executed via JavaScript.

Private Sub Button1_Click(ByVal sender As System.Object, _
       ByVal e As System.EventArgs) Handles Button1.Click
  Dim sText As String = "Hello!"
  ClientBrowserVBScript("", "msgbox(" & Chr(34) & sText & Chr(34) & ")")

  'Pass addidional Variables

  Dim sAdd1 As String = "sServerName=" & _
           Chr(34) & Server.MachineName & Chr(34)
  ClientBrowserVBScript("SayHello.vbs", sAdd1)
End Sub
 
Sub ClientBrowserVBScript(ByVal sVBScriptName As String,_
         Optional ByVal sAddScript As String = "")
  Dim sc As String = Replace(sVBScriptName, ".", "")
  Dim sb As New System.Text.StringBuilder
  
  'Create a hidden Textarea as Script-Container

  sb.Append("<div style='position:" & _
       "absolute;top:100;left:100;visibility:hidden;'>")
  sb.Append("<textarea name='ClientBrowserVBScript" &_
     sc & "' id='ClientBrowserVBScript" & _
     sc & "' cols='100' rows='10'>" & vbCrLf)
  sb.Append("On Error Resume Next" & vbCrLf)
  sb.Append(sAddScript & vbCrLf)
  
  'Append the VBScript from the Project

  If sVBScriptName <> "" Then
    Dim fs As New StreamReader(Server.MapPath("ClientScripts/" _
                                                  & sVBScriptName))
    sb.Append(fs.ReadToEnd)
    fs.Close()
  End If

  sb.Append("</textarea></div>" & vbCrLf)
  'Suppress Javascript-Error

  sb.Append("<script>" & vbCrLf)
  sb.Append("onerror = stopError;" & vbCrLf)
  sb.Append("function stopError()" & vbCrLf)
  sb.Append("{" & vbCrLf)
  sb.Append("return true;" & vbCrLf)
  sb.Append("}" & vbCrLf)

  'Extract the Script

  sb.Append("sScript = window.document.getElementById(" _
      & Chr(34) & "ClientBrowserVBScript" & _
      sc & Chr(34) & ").value;" & vbCrLf)

  'Execute VBScript under Javascript 

  sb.Append("javascript:window.execScript(sScript, " & _
              Chr(34) & "VBScript" & Chr(34) & ");")
  sb.Append("</script>")
  Page.RegisterClientScriptBlock("ASPXClientBrowserVBScript" _
                                                  & sc, sb.ToString)
End Sub