SharePoint Form Validation supports client-side validation for SharePoint list field data. It provides 4 standard validation types (Required Validation, Regular Expression Validation, Compare Validation, and Range Validation) for input content checking when users create a SharePoint list item using New Form or edit an item using Edit Form. The Administrator can configure the 4 validations and customize the warning error messages for most columns in a list. The Required Field Validator is used for setting whether a column should not be null. Regular Expression Validator is used to check whether inputted content is against a regular expression. Range Validator checks that a value is within a certain range and Compare Validator plays an important role when data is set to be compared with other data.