Add code to perform server side validation in response to the submit button being clicked. Here are the business rules we want to enforce (remember this will be server C# code in the frmPersonnel code behind): Fields may not be empty or filled with spaces. If any field is empty, turn that field background color to yellow and add to/create an error message to be shown in the error label. The end date must be greater than the start date. If the end date is less than the start date, turn both date fields yellow and add to/create an error message to be shown in the error label. If all fields validate properly then the session state items should be set properly and the user should see the frmPersonnelVerified form with all the values displayed.