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I'm trying to get HTML5 offline storage working in a basic way. I read the information on DiveIntoHTML5 and it seems to make sense, but it just doesn't seem to be working for me. I wondered if someone could help me to debug this.

Basically I've set up a home page for the application, index.htm. So my application is on the web at http://www.mydomain.com/online/index.htm. Users will visit this page, where they'll ordinaraily do all of their stuff day-to-day. Visiting this URL will create a bunch of cached files so they can then visit http://www.mydomain.com/offline and view a working version of the application when they're offline.

The top few lines of code in the online homepage are:

<!DOCTYPE html>
<html manifest="cache.manifest">

I've generated a plain text file called 'cache.txt' and added the following content to it in Notepad:


I've then renamed this file to 'cache.manifest' and uploaded it to the root of the online application (at the same level as my home-page) so that it's accessible at http://www.mydomain.com/online/cache.manifest.

The hosting company have supposedly added the content type of 'text/cache-manifest' to all files with the extension of .manifest in IIS. I think this is working because when I view the file in Firefox at http://www.mydomain.com/online/cache.manifest Firebug tells me the content type is:

Content-Type    cache-manifest

Or should this be returning 'text/cache-manifest'? Perhaps this is the problem?

When I view the offline storage folder on my system (C:\Users\Me\AppData\Local\Mozilla\Firefox\Profiles\b12u6xza.default there's nothing in there related to this domain at all.

Can anyone suggest what might be going wrong - as I'm a little stumped?

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2 Answers

First of all, the specification have changed, you should now use .appcache as manifest extension.

Second, the mime type should be defined as you say text/cache-manifest. I'm not really related to IIS but seems like there's two ways to add this MIME type , either trough IIS administration UI or via web.config file

Also, I would recommend you testing this with Google Chrome, since its console show all the manifest parsing data and errors, including when the manifest MIME type is not being correctly recognized.

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the spec says the file can have any extension –  pinoyyid Nov 9 '13 at 19:40
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try to add these lines in httpd.conf ..this might help you

AddType text/cache-manifest .manifest

<IfModule mod_expires.c>
ExpiresActive On
ExpiresByType text/cache-manifest "access plus 0 seconds"
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Is this for Apache, or IIS? My environment is Windows/IIS. –  Dan Oct 4 '11 at 10:30
this is for apache .. –  Aman Agarwal Oct 4 '11 at 10:32
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