Develop a Google Chrome Web Extension

General information for the business: I use a Page Monitor extension and require a faster version
Description of every module: I have been using the following Google Page Monitor extension :
https://chrome.google.com/webstore/detail/page-monitor/pemhgklkefakciniebenbfclihhmmfcd?hl=en

It is perfect for my needs bar one area which is I am only able to reduce the time it takes to look for changes down to 5 seconds, I require ideally for it to be constantly monitoring the page / area and immediately notify me of any changes or whichever is the fastest it is able to do without losing stability.

The design and other functions are all perfect otherwise and necessary.
Description of requirements/functionality: The key requirements are exactly the same as the extension I am using but with a shorter monitor refresh time, the main features are:
1. To monitor a web page at the fastest rate possible e.g. 0.1 seconds providing it does not affect stability.
2. To allow me to choose an area/section of the page as opposed to the whole page.
3. To sound an alarm when a change has been found.
4. To allow me to monitor many pages at one time
Extra notes: