How can I get the color of any specified pixel on a web page?

https://chrome.google.com/webstore/detail/eye-dropper/hmdcmlfkchdmnmnmheododdhjedfccka?hl=en

Ok a few more details here....

With Chrome plug in you can load up your page, and use the little dropper tool to select a segment of the page that you are interested in finding out the color. It's straight forward, but to your "Edit" its sort of screen scraping. Not sure if you can or can't use chrome.

If you can't use a plug-in, do you have the ability to select the html element via right click?

Can't be done w/ script+tricks. Maybe via a plugin

If you can set up a server-side browser to render pages for you - that might work.

You could use the html2canvas library to rerender your webpage to a canvas whenever your DOM updates, then grab the pixel information from the canvas.

However, it sounds like what you're trying to achieve might be possible to do with css filters. Here's a demo of what css filters can do. You would need to render two layers with the same HTML, where the top layer has the filter applied to it and is cropped to cover only the desired area.