public class ContactFormController {
    
    public string FirstName { set; get; }
    public String LastName { set; get; }
    public String Email { set; get; }
    public String Phone { set; get; }
    public Boolean disabl {set;get; }
    Contact con = new Contact();
    
    
   // checking condition and  passing value 
   public ContactFormController()
       {
        disabl=true;
         
       }
    
    public void change(){
         System.debug('Change is Running now');
        if (String.isNotBlank(FirstName) && String.isNotBlank(LastName) && String.isNotBlank(Email) && String.isNotBlank(Phone)){
            disabl = false; // If all fields are filled, enable the submit button
        } else {
            disabl = true; // If any field is empty, disable the submit button
        }
    }
   
          //saving into contact
          //
    public void insertAcc(){
        try {
            con.FirstName = FirstName;
            con.LastName = LastName;
            con.Email = Email;
            con.Phone = Phone; 
            insert con;
        } catch (Exception e) {
            // Handle the exception here
            System.debug('Error: ' + e.getMessage());
            
        }
          
            // calling next vf page
    
          
          
        
    }

}