First of all, you should add the javascript as an AMD module: http://learn.elgg.org/en/1.12/guides/javascript.html

jQuery will be loaded asynchronously, so it isn't necessarily available when your script is called.

secondly, you're binding on 

#input_form

When your form has the id of

formMedicine

oh, yes, yesterday I have seen and corrected the error without difference. I'll see the url you have writen, thanks so mutch...