This is a tutorial which tells the users how to process a form with php4. The author says to the users about uses of form processing to the users where the simple solution is to check the data after it has been submitted and simply return an error page to them for the blank fields that is left by them. This tutorial provides information to the users that a more ambitious method is to have the form displaying and processing within a single file. This tutorial explains to the users about display mode in which beyond displaying an unobtrusive error message, the form itself must retain the data submitted by the user when error was displayed.