Can't read form values

you save method is wrong. you call the wrong url.

Because the url variable is empty, you send to the wrong controller.

Sir,

When I try to add this line to the save function save_method = 'add';. Still, it doesn't work out. Why is that? I tried the developer's console using Firefox. see the screenshot below

3 request. 2 have a 500er.

Did you press the button 3 times? Can you show me the headers?