Checking if a JSP file is updated

Guys,

To get through some rather tricky cross server security ive decided to have one side that writes to a JSP file all the fields i need then the other side will pick this up and check if its complete.

Is there anyway to check a JSP file after the page has been loaded for example when a close button is pressed to see if the required variables/fields are present before letting them continue?

Thanks

of course u can do this

Ok,

Any ideas how?

When the user clicks the Close button need to load in a dynamic JSP file and check if its been written to.

How would i go about this? Someone please

Kazz