It's an exciting time to be a JavaScript developer for Bitcoin. There are a number of JavaScript libraries for Bitcoin. Here is a comprehensive list of alternatives to Bitcore:

- https://github.com/bitcoinjs/bitcoinjs-lib (one of the best)

- https://github.com/indutny/bcoin (Indutny's work is found throughout Node.js and is the basis of elliptic curve cryptography in Bitcore)

- https://github.com/ryanxcharles/fullnode (ex-developer of Bitcore and now engineer at Reddit behind Reddit's crypto currency initiative)

- http://cryptocoinjs.com/ (disclosure: I started this one)

Here is an older article that I wrote about understanding how an Address is created (still valid, but using an older version of bitcoinjs-lib): http://procbits.com/2013/08/27/generating-a-bitcoin-address-...

The cool thing is that you can use test Bitcoins without any risk to learn how to program for Bitcoin. Use these faucets: http://tpfaucet.appspot.com/ and http://faucet.xeno-genesis.com/

Here is a very simple wallet that I built to demonstrate how easy it is to build one: https://github.com/coinbolt/simple-wallet

Finally, an open source app to test the purchasing experience of Bitcoin: https://github.com/coinbolt/catshop