Beware. This specification is no longer in active maintenance and the Web Applications Working Group does not intend to maintain it further.
This document was on the W3C Recommendation track but specification work has stopped. The specification reached an impasse: all interested implementors have used the same SQL backend (Sqlite), but we need multiple independent implementations to proceed along a standardisation path.

从上面的信息来看,简单说就是不建议使用该技术,请继续阅读IndexedDB或Web Storage的部分