Check if file has changed using HTML5 File API

Question

Okay, so I have a program which outputs some specific data to a tab separated variable file.

I had been using Excel to open and view the file contents, however I fou

Answer 1

While T.J. Crowder's answer is correct, Chrome's implementation appears to break the spec.

Each Blob must have an internal snapshot state, which must be initially set to the state of the underlying storage, if any such underlying storage exists, and must be preserved through structured clone. Further normative definition of snapshot state can be found for files.

When a file is selected the input has a snapshot of the contents at that point. Local changes on disk don't update the snapshot.