This site allows users to enter basic loan information into a form and when the user clicks the submit button the information is used to calculate a loan summary which includes: monthly payment, total interest paid, and the last payment date. This site uses server side validation and replaces any value not within a normal range with the calculator default for the form field. In addition, they also use server side code to calculate the items on the loan summary which is then displayed to the user. I personally think that by adding client side validation, it would improve the users experience because it would ensure that the data being submitted is within an acceptable norm and if the data entered was not within this range then it would allow the user to adjust the data.