Great tool for testing XPath Rated 5 out of 5 stars
I was in need to test some XPath expressions but all solutions I could find (mainly, web-based ones) required a document's source to work. That was not acceptable for me as I needed to run XPath on dynamically generated web-pages. So I was even going to write my own FF add-on but found XPath Checker which perfectly matched for my tasks. It's easy to use and gives a visual feedback.
Extremely helpful add-on!