Function is undefined

Hello all. I have a form and I wanted to add a button to this form, I have a server side method and I choose this method as a button Click or button Focus event. I get the following error. Event handler failed with message: 'func$FE48E619C551415A8C3F9D0023594694$_onfocus0' is undefined. Read more http://ift.tt/2j0oolg