在与您的工作区一起在分屏中播放的视频中，您的授课教师将指导您完成每个步骤：

1. •

   Compare client- and server-side validation as you investigate when and where to validate data values to reduce data input errors.

2. •

   Use JavaScript code to check an input field on a form to ensure that it has been filled in and display an error message if the field is empty.

3. •

   Use JavaScript to test the value entered into a form field to determine its length and/or whether it falls within a range of numeric values and display an error message if that is not the case.

4. •

   Test the value entered into a form to ensure that it matches an email address format and display an error message if it does not.

5. •

   Modify HTML code to include built in form validation to check for a range of numbers, a list of values and the correct format for an email address.