Is there any way to enable native JavaScript to read local file on the disk?
no Ajax, no JQuery or other JavaScript library, only use the native JavaScript?
I have searched, but it seems there is no way to do this.
My requirements are that when the Internet can not be accessed, I will show a warning page in the Chrome browser.
HTML5, have a File Api, if you are interested in reading file, just for the reading - MSDN, HTML5rocks.
If you are more interested in the case when the user is offline, and your application needs a storage, you can take a look at localstorage - MDN, diveintohtml5. There is an example how to check if it is available, although CanIUse says it is currently available everywhere. Here is a live example.
Hope this will help, in your case which seems to be the synchronization after being offline.
If you are using JavaScript in a browser, there is no way to access an arbitrary file from the local filesystem like this. XMLHTTPRequest can be used to access files natively without a library like jQuery, but it prevents access to local files as a security measure.
However, you can use a cache.manifest file to set up an offline version of an HTML 5 site/app.
You can use a combination of <input type="file"/> and Javascript's window.FileReader to read file. It has many methods of receiving the data, easiest being FileReader.readAsBinaryString(file); You can only read files that a user has selected from a file browser.
Here's Mozilla Developer Network's documentation on it.
For your uses, however, it seems like developing a Chrome extension would be a better solution to manipulating the way Google Chrome works.
