Bluefish is a powerful editor for webdevelopers and its free & open source. It is available for Linux, FreeBSD, MacOS-X, Windows, OpenBSD and Solaris.
Few notable features:
- Integrate external programs such as make, lint, weblint, xmllint, tidy, javac, or your own program or script to handle advanced text processing or error detection
- Integrate external filters of your liking, pipe your document (or just the current selected text) through sort, sed, awk or any custom script
- Unlimited undo/redo functionality
- In-line spell checker which is programing language aware (spell check comments and strings, but not code), requires libenchant during compilation2
- Auto-recovery of changes in modified documents after a crash, kill or shutdown
One thing I miss in Bluefish is that it does not have native support for git.
Brackets @ Github, https://github.com/adobe/brackets and it has more than 15K stars & 3K forks.
This is the best tool to check for information, errors, warnings, etc. and has tons & tons of features.
The Web Developer extension adds various web developer tools to a browser. The extension is available for Chrome, Firefox and Opera, and will run on any platform that these browsers support including Windows, OS X and Linux.