You must use the Enumerator object instead of the for..in loop to iterate members of a collection (in JScript). Using the for..in loop for objects and arrays: var a, key, s = ""; a = {"a" : "Athens" , "b" : "Belgrade", "c" : "Cairo"} for(key in a) { s += a[key] + "&ltBR>"; } Using Enumerators to iterate members of a collection: var e = new Enumerator(colAdapters) for(; ! e.atEnd(); e.moveNext()) { var buf = new String() buf += 'Host name:\t ' + e.item().DNSHostName + EOL buf += 'IP address:\t ' + e.item().IPAddress(0) + EOL buf += 'DHCP enabled:\t ' + e.item().DHCPEnabled + EOL WScript.echo(buf) } var e = new Enumerator(Request.Form) while(!data.atEnd()) { Response.Write(data.item() + ': ' + Request.Form(data.item()) + '<BR>') data.moveNext() } var e = new Enumerator([collection]) e.atEnd() e.item() e.moveFirst() e.moveNext() collection - Optional. Any object that implements the IEnumerable interface, such as an array or collection.