(Classic ASP) Call a JavaScript Function Returning a Boolean

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Demonstrates how to call a JavaScript function that returns a boolean.

Note: This example requires Chilkat v11.4.0 or greater.

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<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body>
<%
success = 0

' This is the JavaScript function we'll call:

' function isEven(number) {
'     return number % 2 === 0;
' }

set sbScript = Server.CreateObject("Chilkat.StringBuilder")
success = sbScript.Append("function isEven(number) { return number % 2 === 0; }")

set js = Server.CreateObject("Chilkat.Js")

set result = Server.CreateObject("Chilkat.JsonObject")
result.EmitCompact = 0

' Call Eval to add the function to the context's global object
success = js.Eval(sbScript,result)
If (success = 0) Then
    ' Examine the result for an exception.
    Response.Write "<pre>" & Server.HTMLEncode( result.Emit()) & "</pre>"

    ' Also examine the LastErrorText.
    Response.Write "<pre>" & Server.HTMLEncode( js.LastErrorText) & "</pre>"
    Response.End
End If

' ------------------------------------------------------------------------------
' Call the function isEven(8)

set funcCall = Server.CreateObject("Chilkat.JsonObject")

' Create JSON specifying the function name and arguments

' {
'   "name": "isEven",
'   "args": [ 8 ]
' }

success = funcCall.UpdateString("name","isEven")
success = funcCall.UpdateInt("args[0]",8)

success = js.CallFunction(funcCall,result)
If (success = 0) Then
    ' Examine the result for an exception.
    Response.Write "<pre>" & Server.HTMLEncode( result.Emit()) & "</pre>"

    ' Also examine the LastErrorText.
    Response.Write "<pre>" & Server.HTMLEncode( js.LastErrorText) & "</pre>"
    Response.End
End If

Response.Write "<pre>" & Server.HTMLEncode( result.Emit()) & "</pre>"

' Output:
' {
'   "type": "bool",
'   "value": true
' }

retval = result.BoolOf("value")
Response.Write "<pre>" & Server.HTMLEncode( retval) & "</pre>"

' Output:
' 1

%>
</body>
</html>