Why don't work button???

Why don't work button???

$ ( document ). ready ( function () {

$ ( "#createStudentForm" ). unbind ( 'submit' ). bind ( 'submit' , function () {
             var form = $ ( this );
             var formData = new FormData ( $ ( this )[ 0 ]);
             var url = form . attr ( 'action' );
             var type = form . attr ( 'method' );
            

             $ . ajax ({
                 url : url ,
                 type : type ,
                 data: formData ,
                 dataType: 'json' ,
                 cache: false ,
                 contentType: false ,
                 processData: false ,
                 async: false ,
                 success : function ( response ) {    
                     var data = JSON . parse ( response );                
                    
                     if ( response . success == true ) {                      
                         $ ( "#add-student-messages" ). html ( '<div class="alert alert-success alert-dismissible" role="alert">' +
                         '<button type="button" class="close" data-dismiss="alert" aria-label="Close"><span aria-hidden="true">&times;</span></button>' +
                         response . messages +
                         '</div>' );  
                            

                         manageStudentTable . ajax . reload ( null , false );
                         $ ( '.form-group' ). removeClass ( 'has-error' ). removeClass ( 'has-success' );
                         $ ( '.text-danger' ). remove ();
                         clearForm ();
                    }   
                     else {                                  
                         if ( response . messages instanceof Object ) {                           
                             $ . each ( response . messages , function ( index , value ) {
                                 var key = $ ( "#" + index );

                                 key . closest ( '.form-group' )
                                . removeClass ( 'has-error' )
                                . removeClass ( 'has-success' )
                                . addClass ( value . length > 0 ? 'has-error' : 'has-success' )
                                . find ( '.text-danger' ). remove ();                         

                                 key . after ( value );

                            });
                        }
                         else {                          
                             $ ( "#add-student-messages" ). html ( '<div class="alert alert-warning alert-dismissible" role="alert">' +
                             '<button type="button" class="close" data-dismiss="alert" aria-label="Close"><span aria-hidden="true">&times;</span></button>' +
                             response . messages +
                             '</div>' );                      
                        }                           
                    } // /else
                } // /success
            }); // /ajax

             return false ;
        }); 
    });