HOW TO detect unused CSS style definitions

As your web app project & the team size get larger,  there is a chance that the CSS style definitions within the stylesheets grow uncontrollably due to lack of coordination among the developers. This could lead to duplicate style definitions & gradually this could impact web page performance.

Luckily, there are tools to detect unused CSS selectors per page & weed them out manually -

• Dust-Me Selectors is a Firefox Extension (Firefox version 4 is not currently supported) that scans all the definitions inline & within external stylesheets and reports the unused ones.

• Audit tab within Google Chrome Developer Tools (Ctrl+Shift+I) lists unused selectors as part of its performance recommendations 

Also see:
HOW TO cut & paste just the text in a browser, not the formatting