TypeError related to IDBCursor.PREV

[lovett]

There's a minor flaw with the IndexedDB object detection logic. IDBCursor is set to either window.IDBCursor or window.webkitIDBCursor, but if neither of these exist there is no fallback. That's not so bad by itself, but it means the subsequent attempt to set IDBCursor.PREV and IDBCursor.NEXT may throw a type error because they are setting a property on an undefined value.

I ran across this in an application that bundles jquery.indexeddb.js into a larger file that concatenates several libraries. This causes clients that don't support IndexedDB to receive this file even though they don't otherwise invoke it. The ones without support throw the type error because they still perform the object detection.

This could be fixed by setting IDBCursor to a an empty object if nothing more suitable is available. Or alternately by not setting prev and next if IDBCursor is undefined.

[axemclion]

This is a good suggestion. @lovett, can you please send a pull request for this to the incoming-pr branch ?