We need a browser/web based PDF viewer that should support the following:
PDF documents can be viewed in iframe and this should be supported in Internet Explorer, Mozilla Firefox and Google Chrome.
Our users should be able to navigate through the documents by bookmarks and annotations in PDF document that is opened in iframe in web browser.
Our users should be able to add/edit/delete annotations in PDF document that is opened in iframe in web browser.
Edited PDF files should be automatically saved in browser cache without user intervention. That should result in annotations being automatically saved to the browser cache pdf document.
Everything should work in “offline” mode. Our web site supports HTML 5 cache and site content is available even when user is not connected to the internet.
Based on your requirements you should use PDFTron WebViewer, which works with all major Web platforms, devices, and browsers. The viewer can be directly embedded and customized within any HTML5, Silverlight, or Flash application and content can be instantly accessed from any system or device. You can find more info here: http://www.pdftron.com/pdfnet/webviewer
The WebViewer supports #1 and #2 right out of the box.
For #3, we currently save annotations as an XFDF file (basically saving annotations as XML elements). Annotations can be saved either automatically in a pre-determined interval, or you can make use of a Save Annotations button if you wish. Then, every time the document is reloaded, the WebViewer fetches the XFDF file and load the annotations back into the document.
For #4, offline mode is an up-coming feature and should be ready in the next update release.
To see the WebViewer in action you can look at these online samples:
Here is the link to the WebViewer trial download: