Compare local text files with text files on the web

I need a quick way to compare thousands of static HTML text files located on my local computer, with the same files found on my website. Then let me know if they are different. My website is popular and gets hacked alot (defaced) and they replace all my advertising code with their own. I have my hosts IT department checking to stop them but want a quick way to check if the files were defaced. Need a way to daily check these files, thousands of them in about five different directories, and let me know which were altered. I am ok with it being created in any programming language as long as the code is readable and kept on my computer (not stored online). All files in a single directory are stored in a single directory online, so the ability to add an entire directory of files and point to single web address is required. Also the ability to add or remove single files. I am open for quick inexpensive ($30 to $250 USD) and also small ($250 to $750), it just depends on the features I can get for the price.