However, although SQL Server Reporting Service (SSRS) is a web app but as a default it does not have parameter (user input) validation. We have to write a Code at Report Properties Menu and implement it on Report Parameter.
The SSRS Parameter Validation mechanism must check if parameters do not meet specific criteria then related sql query is not running.
I use SSRS 2005 and AdventureWorks database to demonstrate creating this validation. I will show Purchase Order info based on Order Date.
Parameters are range of Order Date (Order Date From & Order Date To) but the range must not exceed 365 days or 1 year.