Here is an overview I wrote. This is based on a lot of conversations and emails to non-technical startup people who wanted to learn a bit about the tech. This same material was also given as a talk at Wharton's Venture Initiation Program. Some beginning programs have told me they found it useful also:

http://illuminatedcomputing.com/posts/2014/03/basics-of-web-...

Note there are a few "lies" for the sake of simplifying, and some comments are a little dated, but hopefully it is helpful for you!

EDIT: Let me add, if you're wondering about what language & framework to choose, my advice is it doesn't matter too much, so don't spend much time on this decision. Go with your taste/enjoyment and dive in. You can't make a good choice from reading other people's generalities, so don't try. My preference is Rails, but tastes differ. (I will offer my own generalities though: Rails is best at rapid development and adaptability, Python is best at stats/machine learning, and I'd don't know what Java & C# are best at. For "best at safety/correctness" maybe I'd choose Haskell. :-)