We use Lawson software. It is proprietary and we do not have access to the code. Recently, there has been an update to Lawson and we are not seeing the Alert() windows that come from JavaScript. Lawson people are asking us to figure it out. I downloaded Fiddler to see if I could tell if the event was firing. I have very little Fiddler experience and don't know if I'm approaching how to answer this question correctly. How can I tell if a JavaScript event is firing without debugging the source code? Would Fiddler be able to tell me that?
No, Fiddler won't be able to tell you that. Fiddler is a tool used for viewing HTTP requests, but javascript alerts are unrelated to HTTP requests. I'm not aware of a way you can debug javascript code in an arbitrary application without access to the source code.