Is there a way to monitor particular content changes in websites in daily basis?

I want Monitor some content changes which is present in web site in daily basis using any scripting or browser plugin.... 

for example, i want i to get notified job openings in particular websites based on my query without subscribing their subscription. i want to get notified when it matches my criteria on daily basis.. is their any script or browser plugin available for that? can i achieve this using python script to trace changes available... How can I achieve this?