adsolute beginner needs help should be simple

[dpkdayton]

I am an absolute beginner when it comes to javascript. I am working with ESRI ArcIMS which uses javascript. I am hyperlinking jpg's to parcels in a web mapping application. Here is my problem. The images are divided up into directories. When the user clicks on a parcel on the mapping web site it brings up the jpg. Problem is not every parcel has a photo. I need to scan the directory to see if the photo exists, if not display a default image.
How do I do this in js? How do I comare a file name from the hyperlink on the web site to the files in the directories?
Any help would be apprieciated.
Thanks,
Doug Kotnik

[AdamGundry]

While it might be possible to cobble something together in JavaScript, its file access capabilities are next to none and you can't rely on it being available on all user's machines. A much better solution would be to use a server-side scripting language such as PHP, or whatever your current system is written in.

Adam