Komodo Edit is a free, open source, multi-platform, multi-language editor for dynamic languages and Ajax technology, including Perl, PHP, Python, Ruby and Tcl; plus support for browser-side code including JavaScript, CSS, HTML and XML.

Background syntax checking and syntax coloring catch errors immediately, while autocomplete and calltips guide you as you write. Available on Windows, Mac OS X and Linux. XPI extensions allow you to create your own plug-ins. XPI extension support provides the same capability as Firefox, with all standard Mozilla APIs based on XUL, XBL, and XPCOM, plus our own for Python and JavaScript.

Features
Multi-language editor
Advanced support for:
* Browser-side languages: CSS, HTML, JavaScript and XML
* Server-side languages: Perl, PHP, Python, Ruby and Tcl
* Web template languages: RHTML, Template-Toolkit, HTML-Smarty and Django

Autocomplete and calltips
* Write code faster and shorten the learning curve with code completion that guides you as you work
* CSS, HTML, JavaScript, Perl, PHP, Python, Ruby, Tcl, XML and XSLT.
* Schema-based XML/HTML completion
* Multiple-language file support, such as CSS and JavaScript completion in HTML
* Support for adding third-party libraries
* Interpreter

Windows x86 or x86_64 processor, 500 MHz (or faster) with 256 MB RAM