Per vedere la quota rimasta nel browser From http://stackoverflow.com/questions/10988569/what-are-the-storage-limits-for-the-indexed-db-on-googles-chrome-browser

used.quota.js

// Request storage usage and capacity left
window.webkitStorageInfo.queryUsageAndQuota(webkitStorageInfo.TEMPORARY, 
//the type can be either TEMPORARY or PERSISTENT
function(used, remaining) {
  console.log("Used quota: " + used + ", remaining quota: " + remaining);
}, function(e) {
  console.log('Error', e); 
} );