Q:

Loading or getting ready message

i have some web based application that creates a zip file when user asks for it. and it takes around 5 sec of time which is uncertain.. so i want to show him a loading sceen which should disable my main screen for the time being and show loading oo processing animation something..
i am using jsp servlets
Update: i dont want to use jQuery
Edit: implemented using jQuery but want to do the same without it
thanks.

A:

Use jQuery to lock browser screen and show loading process. You could use ajax to make requests and receive responses asynchronously.
Why use jQuery?

It uses KISS principle - Keep It Simple Stupid
It has very good documentation and tutorials
The community is very active, helpful, and warm
The core file’s packed size is small
It deploys almost use-at-will approach
It has strong logic and workflow and is easily extensible

Since you do not want to use jQuery you have to deal with javascript basics like manipulating the DOM.
Basic ajax tutorial:

http://www.ibm.com/developerworks/web/library/wa-ajaxintro1.html
http://www.ibm.com/developerworks/web/library/wa-ajaxintro2/
http://www.ibm.com/developerworks/web/library/wa-ajaxintro3/

This tutorials are on DOM manipulation:

http://www.ibm.com/developerworks/web/library/wa-ajaxintro4/
http://www.ibm.com/developerworks/web/library/wa-ajaxintro5/
http://www.ibm.com/developerworks/web/library/wa-ajaxintro6/

