The HTML markup language has build in codes to provide forms. In forms the user can input fields fill out, in text fields of several lines text enter, from lists of entries selects and so forth.If the form is filled out, the user can click on a Button, in order to process the form. The form contains special tags to indicate what happens with the data of the filled out form. For example send the data by E-Mail or process the data with a CGI program on the server.Generally, the major problem is the form validation.