JavascriptBlockchain. n this tutorial, we will see How To Create Blockchain In JavaScript. Blockchain keeps the record of all data exchanges — this record is referred to as the “ledger” in the cryptocurrency world, and each data exchange is the “transaction.“ Every verified transaction is added to the ledger as a “block.” It utilizes the distributed system to verify each transaction — the peer-to-peer network of nodes. Once signed and verified, a new transaction is added to the blockchain and cannot be altered.