Running a JavaScript program : 

 (1) create the files (*.html, *.js, *.css, *.png, ...)
 	The HTML file is what holds the program together,
 	either containing the javascript or pointing to the *.js file.
 (2) load the html file from a browser.
 
========================================================================

Browsers with JavaScript debugging :

 FireFox 
   with extensions : 
     Web Developer
     Live HTTP Headers
     Linkification
     Venkman Javascript debugger
     greasemonkey - website customization
     xMirror

======================================================================= 

HTML text editors

http://en.wikipedia.org/wiki/Comparison_of_text_editors

 xemacs / emacs    (unix,mac,windows open source)
 vi  / vim         (unix,mac,windows open source)
 pico / nano / joe (unix)
 TextPad           (windows, free demo) www.textpad.com
 NotePad++         (windows, free) notepad-plus.sourceforge.net
 Edit+             (windows) www.editplus.com
 BBedit            (mac, commercial)
 TextWranger       (mac, free)  

 HTMLPad

WYSIWYG html editors
 Amaya (W3C open source)
 Mozilla Composer
 
--------------

newlines : 
 DOS   (CR/LF)
 Unix  (LF)
 Mac   (CR)

---------------------------------------------------------------------------------

Jim's suggestion (links as of Nov 2005)

 ** Macintosh     TextWrangler   http://ven.barebones.com/TextWrangler_2.1.dmg

 ** Windows       NotePad++      http://notepad-plus.sourceforge.net/uk/download.php
      http://prdownloads.sourceforge.net/notepad-plus/npp.3.3.Installer.exe?download

 ... or for the brave : xemacs / emacs | vi / vim
     (More powerful but more complicated to install and master.
     Most serious hackers I know use vi or emacs or a variant.)
 
     * terminal versions of emacs and vim are part of the default Mac OS X;
       just type "emacs" or "vim" in a terminal window.

     xemacs install on Mac :
       via http://xemacs.darwinports.com
       i) install X Window System for Mac (X11 1.1 XFree86 4.4.0)
         http://www.apple.com/downloads/macosx/apple/x11formacosx.html
       ii) install darwinports (http://darwinports.com)
         http://darwinports.org/downloads/DarwinPorts-1.1.dmg & adapt shell PATH
      then iii) PortAuthority GUI, http://www.wordtech-software.com/dpgui.html,
           iv) install XEmacs via PortAuthority point-n-click
      or iii) command line : sudo port installl xemacs
      Invoke it via command line: $ xemacs & (or /opt/local/bin/xemacs &)
      or by installing that command into X11 menu

     xemacs install on windows
       http://www.xemacs.org/Download/win32/
       both windows native or cygwin unix-for-windows versions available