Windows Script Host and JScript don't know anything about constants in type library enumerations. You need to explicitly define these constants in your script:
var olRuleReceive = 0;
var olRuleSend = 1;
So, have I need to find out about the number of constant value myself? Do you have some way to search that value from MSDN document?
You have several options:
Look up the constant values in the Outlook developer reference in MSDN.
Look up the constant values in the VBA Object Browser (see Bill_Stewart's comment).
Place your code into a Windows Script File (.wsf) and import the Outlook type library using the <reference> element. In this case you can use all Outlook enumeration constants without having to declare them.
<job> <reference object="Outlook.Application"/> <script language="JScript"> WScript.Echo(olRuleSend); // 1 </script> </job>