This page contains some links I have found helpful and some I haven't checked out but seem interesting.
W3C Markup Validator (online, free)
W3C CSS stylesheet validation
W3C broken link checker
<HTML> Validator (commercial product)
Valid DOCTYPE declarations (dtds)
HTML tag reference
HTML5 tag reference
HTML Event reference
HTML Color reference
XHTML Tag reference
CSS reference
CSS3 reference
HTML tutorial
HTML5 tutorial
XHTML tutorial
CSS tutorial
CSS3 tutorial
W3C: Index of Attributes (HTML 4.01)
W3C: Obsolete Features (HTML 5)
List of Deprecated Attributes Still in Widespread Use (2007)
Adobe Forums (Dreamweaver)
Web development forum
V7 Network
Wedost SEO Internet Marketing Forum
CSS Sizing Guidelines
CSS Drop-Shadow Techniques
New CSS3 Cursor Styles
HTML5/CSS3 Browser Support Info
Not Just a Grid
Mobile-Friendly Design Skeleton
Less Framework
Free CSS Templates
Dreamweaver CSS Templates for beginners
New Dreamweaver Starter Pages (free)
Ultimate Multi-Column Layouts (free)
Superfish Menus
How to change localhost to a domain name
Safe Fonts to Use in Web Sites
CSS Sizing Guidelines
W3Schools: HTML Character Sets
Character encoding (Windows-1252, ISO-8859-1, UTF-8)
Windows-1252 (Wikipedia)
Encoding Problems: Treating UTF-8 as Win-1252/ISO-8859-1
Unicode Tools: Windows-1252 code page (w/ links to other code pages and resources)
Perl documentation
Modern Perl (book - free download)
CGI/Perl Taint mode FAQ
How to Identify a Good Perl Programmer
Why You Can't Hire Great Perl Programmers
x
Git documentation page
Git Reference (basic tutorial)
Pro Git (blog/on-line book)
GitWeaver (Git extension for Adobe Dreamweaver)
TortoiseGit (Git for Windows)
Git downloads
Git Tools/Hosting
HTTP Status Messages
HTTP status codes
Web Robots Page
Comprehensive Guide to .htaccess
What is href rel?
Using the link relationship attribute rel="nofollow"
Computing with Accents, Symbols & Foreign Scripts
.htaccess Tips and Tricks | More...
Specify Your Canonical (Google Webmaster Central Blog 2/12/09)
About rel="canonical" (Google Webmaster Tools Help: Matt Cutts video)
Web Design Tutorials
Page Layout 101
HTML5 boilerplate
Taking a Fireworks comp to a CSS_based layout in Dreamweaver (pt. 1/3)
What's new in Dreamweaver CS5 CSS layouts
From table-based to tableless web design with CSS
Create a favicon.ico
PVII tutorials and articles (Accessibility, CSS, images, navigation, servers)
Single-Page Websites: Examples and Good Practices
Example: single-page website design package (Mercury)
W3Schools
CSS Tricks
SEO Consultants
WebDeveloper.com
Web Design (Matthew James Taylor)
WebmasterWorld
Internet.com
Google SEO News and Discussion Forum
STOP badware - tips for cleaning & securing your website
SQL Injection
Securing a contact form
WWW Security FAQ
x
perlsec
CGI/Perl Taint mode FAQ
x
ask.com blog
bing Webmaster Center blog
bing Search Engine Marketing (SEM) forum
Search Engine Ranking Factors (SEOmoz 2011)
SEO Starter Guide (updated) - Google
The Reaction Engine (keyword analysis tool)
Common errors that can tank a site
bing indexing problems
bing indexing problems
Top 5 Social Media Scams (Norton)
Alternatives to the Big 3 Browsers
Google Guitar (Les Paul, R.I.P.)
Google Pac-Man
Resume Bloopers Part: 1 2 3 4
MIT OpenCourseWare
Stanford Coursera [article: Delay of January 2012 classes]
- Machine Learning
Free Online Courses from Top Universities (organized by topic)
Class Central (combined list)