title: Check if file has changed using HTML5 File API
body: <p>Okay, so I have a program which outputs some specific data to a tab separated variable file.</p>
  
  <p>I had been using Excel to open and view the file contents, however I found excel's insistence on locking every file it opens to be incredibly annoying as my program would crash if I left the file open in Excel... but I would really like the data to neatly update after each run of the program, so I don't have to close and re-open the file all the time.</p>
  
  <p>So, I decided it would be easiest to use Javascript to parse the file and display it in a html table, and it was. I knocked something together in no time. Now my program doesn't crash if I leave the file on display, however, it still doesn't update... and I have to open the newly generated file each time.</p>
  
  <p>So, I was wondering if there was a mechanism by which my Javascript could be somehow notified of a change to the file by another process? I know this is unlikely, but I would like to avoid simply polling the file for obvious reasons.</p>
  
  <p>I am very familiar with JS, but HTML5 and the new APIs are all new to me.</p>