HTML 5 filesystem access Type Error

Question

I'm working on a webapp and I'm trying to access directories using the filesystem API. I need to request a quota from the user before accessing the directories according to specification. I should do something like this:

...
navigator.webkitPersistentStorage.requestQuota(PERSISTENT, 1024*1024, 
function(gB){
   window.requestFileSystem(PERSISTENT, gB, onInitFs, errorHandler);
}, function(e){
   console.log('Error', e);
})
...

Everytime I do this I get a **TypeError: Type error** message. Please what am I doing wrong? Thanks in advance.
NB: onInitFs and errorHandler have been defined I just didn't include the code here.

Answer 1

this version, from https://developers.google.com/chrome/whitepapers/storage seems to at least get further along:

window.webkitStorageInfo.requestQuota(PERSISTENT, 1024*1024, function(grantedBytes) {
  window.webkitRequestFileSystem(PERSISTENT, grantedBytes, onInitFs, errorHandler); 
}, function(e) {
  console.log('Error', e); 
});

it's window instead of navigator...

Answer 2

I was having the same issues and someone posted the solution, found at filesystem-api-not-working-in-chrome-v27-v29

navigator.webkitPersistentStorage.requestQuota(1024*1024, 
  function(gB){
  window.requestFileSystem(PERSISTENT, gB, onInitFs, errorHandler);
}, function(e){
  console.log('Error', e);
})

You have to remove the PERSISTENT from navigator.webkitPersistentStorage.requestQuota(...)