master page and content page interaction

[mrjoka]

hi friends;
i'm stuck in a web site and i hope you can help me.
i'm working in a statistic web site where i'm using mastre page(this is the first time i'm working with master page) in this mastre page i have a callendar, and 2 drop down list and a tree view, this tree view has a sitemap datasource. in the tree view i have links to many other web pages. my problem is that when i select a value in the drop down list the value is sent to the other page and according to this value i'm querying the database and displaying some griedview and graph, now when i change the value in the DDL the values in the gried view changed but the value of the drop down list turns back to the default view, just in the drop down list. also for the callendar i have a function that disable the date bigger than today so when i run the page the first time the function is called but when i click in a page in the tree view the function does not fired.
i want for the content page to remember all the the functions for the drop down list and the callendar.
any suggestion will be very helpfull

thanks