Web Design Institute In delhi Previously, Common Gateway interface (CGS) was considered as the standard for processing the forms. Once the user has filled in the form and clinks the submit button, The entire form data is sent to the web server for validation CGI scripts do this validation and other form processing activities. CGI Scripts can be written using "C" or perl. Even Small Validations such as, Checking whether the user has not left the name field empty, has to be done at the server side. This is a time consuming process, as the data form has to be sent to the server, processed and sent back to the user through the browser.