Alt Attribute Finder Tool

I am looking to fix some of the code on some client websites, and I want to start by find all the image tags that lack the alt attribute.

The issue is that some of these sites have hundreds of thousands of pages, meaning that a manual search would be hell.

Does anyone know of an automated tool (preferably over http, rather than local) that can crawl a whole site and tell you where your missing alt attributes are?

Ugh, I’d like to know this also. The old HomeSite program would do something relatively comparable, though only locally.