HTML model dialogue box issue

Below is my dialogue code and the issue is that when I submit it doesn't show error and it get's closed
I want to shoe that error on that form itself.
I have used form validation where it doesn't works and it only doesn't work on this particular model

    

        

            
            

                

                    

                        
FEEDBACK FORM
                        

                            

                                Name
                                
                                

                                
                            
                            

                                Mobile
                                
                            
                            

                                Email ID
                                
                                

                                
                            
                            

                                Feedback
                                <?php if(isset($record[0]['feed_desc'])){ echo $record[0]['feed_desc']; }else{ echo set_value('feedback'); } ?>
                            
                            
                             Cancel