Bootstrap Registration Form With Validation Codepen Code Example
		 Example: form validation javascript bootstrap  < script >            // Example starter JavaScript for disabling form submissions if there are invalid fields            ( function ( )  {              'use strict' ;              window . addEventListener ( 'load' ,  function ( )  {                // Fetch all the forms we want to apply custom Bootstrap validation styles to                var  forms =  document . getElementsByClassName ( 'needs-validation' ) ;                // Loop over them and prevent submission                var  validation =  Array . prototype . filter . call ( forms ,  function ( form )  {                  form . addEventListener ( 'submit' ,  function ( event )  {                    if  ( form . checkValidity ( )  ===  false )  {                      event . preventDefault ( ) ;                      event . stopPropagation ( ) ;                    }                    form . classList . add ( 'was-validated' ) ;   ...