This code adds my custom JavaScript to BOTH the administrative area AND the public website:

// from mysite/code/page.php
function getCMSFields() {
Requirements::javascript( 'mysite/javascript/custumL.js ' );
}

I only want to add the JavaScript to the administrative area. It should NOT be loaded on the public website.

Use this in your _config file

LeftAndMain::require_javascript('mysite/javascript/custumL.js');

LeftAndMain is the class which handles the CMS. Though unless you call getCMSFields() on the front end of the site it shouldn't include any JS from that function.

Thanks!

Is this still working in 2.46?
I tried it without success....