I was more or less in your situation. What I did was
I read "javascript, the good parts". It's a good book, but don't take it literally. For example, its use of objects, completely neglecting the new operator and the native object instantiation mechanism is frankly excessive. Hence, learn the prototype-based mechanism well.
take jQuery and learn it by using. Remember that jQuery is a great library to manipulate the web page DOM. add nodes, remove nodes, and much more. jQuery abstracts many browser dependent operations, so you don't go mad with browser incompatibilities.
tinker and when you find yourself in a troublesome spot, use FireBug to find the trouble. Make smaller examples, be very wary of variables introduced without the var keyword, and always keep into account that this refers to the object owning a given routine, and this could be an unexpected one.
Javascript (and JS on the DOM) is a nice language, but its logic can be baffling sometimes. Don't give up. Once you get to understand how it works, it's rather intuitive.
