What is "websql"
Websql is an API designed to support an efficient way of storing and handling data such as an SQL database on the client side, through the browser. However due to limitations in specification was abandoned by W3C who today is working with a solution called Indexeddb.
Even though it has been abandoned, there are several modern browsers that support this technology, but there may be small differences between implementations.
Official specification of Websql: http://www.w3.org/TR/webdatabase/