http://www.html5rocks.com/en/tutorials/dnd/basics/
I don't understand why this is an issue, there are tons of great tutorials: https://www.google.com/search?q=HTML5+drag-and-drop
Step 1 to being a web developer, search Google first. More than likely anything you need done has been done 10,000 times and there are at least 100 tutorials.
Don't be afraid to use libraries such as jQuery,which HTML5 drag-and-drop doesn't require, but I see that you mentioned avoiding it in another comment. Libraries many times also have the advantage of increasing browser support transparently, which is generally a good thing.
Worried about loading time with libraries? Use a CDN such as http://cdnjs.com/, most users will have the popular ones already cached in their browser.
Use StackOverflow if you have questions, that's what it's there for. Hacker News is for... news.