Note: this is a list of resources I've used for clients in the past to help other developers beginning to learn front-end tools get up to speed Here is a list of resources for you to use to become more familiar with html, css & javascript. The resources are categorized by the amount of time or difficulty required for adequate digestion of the information. The easiest/shortest is surfing, resources you can skim through in minutes as you need them. Next is snorkeling, resources better digested over a period of about an hour or more to really go through Lastly, deep diving, resources that cover topics in depth in several hours or more (this doesn't mean you can't pick and choose chapters or sections as you need them, though!).
General Resources:
http://www.w3schools.com/ - surfing - this is a general reference for many web technologies. It is a great reference. it may be the overall best resource on the web for all things web development related.
http://webdesign.tutsplus.com/category/tutorials/htmlcss-tutorials/ - snorkeling - great video tutorials as well as articles
http://coding.smashingmagazine.com/ - snorkeling - a great place for more specific posts
http://alistapart.com/articles - deep diving - this is a site that goes more in depth into concepts as well as specific code examples
HTML (Structure):
http://www.w3schools.com/html/ - surfing - the w3cschools html section
http://www.htmldog.com/guides/htmlbeginner/ - surfing - a great beginner resource (this site also has intermediate and advanced tutorials)
http://www.codecademy.com/tracks/htmlcss - surfing - deep diving - take these courses for as long or short as you want
http://www.abookapart.com/products/html5-for-web-designers - deep diving - read this great, yet short, book on HTML5 for a comprehensive explanation of next-gen practices
CSS (Appearance):
http://www.w3schools.com/css/ - surfing - a popular resource to use at any time to review a css property
http://www.htmldog.com/guides/cssbeginner/ surfing - also can find intermediate-advanced sections here
http://css-tricks.com - surfing - snorkeling - without a doubt the best site regarding CSS out there. A great resource on anything html/css/js related. Covers a lot of advanced topics
http://www.abookapart.com/products/css3-for-web-designers - deep diving - covers the next generation of css layout/appearance
JavaScript (Functionality):
http://www.w3schools.com/js/ - surfing - best way to get started
https://developer.mozilla.org/en-US/docs/JavaScript/Getting_Started - snorkeling - a good resource that has some helpful info along with code examples
http://net.tutsplus.com/tutorials/javascript-ajax/the-best-way-to-learn-javascript/ - surfing - deep diving - nettuts has a great article here on ways to get going with JS
http://www.amazon.com/JavaScript-Good-Parts-Douglas-Crockford/dp/0596517742 - deep diving - A great JS book that really helps one to start to understand the language
UX/Usability/Best Practices:
http://net.tutsplus.com/tutorials/html-css-techniques/30-html-best-practices-for-beginners/ - surfing - great beginner resource here
http://webstandardssherpa.com/ - surfing - some hits and misses here
http://www.smashingmagazine.com/web-design-essentials-examples-and-best-practices/ - surfing - an easy resource to refer to for specific elements
http://bradfrostweb.com/blog/ - snorkeling - Brad has intermediate to advanced UX topics covered
http://www.lukew.com/ff/ - deep diving - Luke is great, but a lot of stuff ventures into UX theory-ish stuff
http://www.labor.ny.gov/ux/ - surfing - deep diving - This is the NYS dept of labor UX site, this is an awesome resource
Some Tools:
http://codepen.io/ - use this site to fiddle around with code easily and see the output without having to create html pages, etc.Very handy!.
http://jsfiddle.net/ - same basic concept as codepen, but more geared towards JavaScript
http://foundation.zurb.com/ - Foundation 4 front-end framework
http://stackoverflow.com/ - great forum, the most trusted on the web. use this to search for questions people have already asked, or pose your own
Don't be intimated by the vastness of the resources outlined here. We suggest for each topic you want to dive in to, take a look, see what appeals to you, and jump in. Then, over time, periodically refer to the deep diving sections to further your skills. I hope this is helpful! Enjoy!