Using Theme() to output html/javascript in user edit
If you just want to add some markup and Javascript, you don't need a submit callback because that's for handling form submissions.

Requirement 1: Add html

Options:


#prefix and/or #suffix form element attributes. (If just simple short html this will do)
#theme to use you custom theme function declared hook_theme and place your markup in your tpl.php file. (If too much markup and want your module/theme to be clean)


Requirement 2: Add javascript

You can use #attached form/form element attribute

In the links, there are example codes that you can follow.