Sorry, but I am litle confus!

Let me expose this scenario : I call a Web application by an access URL. The
application is written in Java. The form makes it possible to write, update
and to remove data. All the data are stored in a database Oracle on a remote
server. The users connect themselves to the application with a username and a
password. In connection mode the application works very well. My answer is:
Could I work offline in my browser after having to download all the Web
application with HTTRACK. Could I add a new element in my application in mode
disconnected and then after connection to make a update of data on tha
database? 

How happens on the levels validations data?
Thank you still to clear up me. 

Regards,
Alex