Cache clean-up operation not working anymore

The cache clean-up operation is not working anymore. The guilty piece of code is:

if ($('#cache_cleanup_details input[name=mode]:checked')[0].value == '1')

in beat/web/backend/templates/backend/scheduler.html around line 728.

It is complaining as follows:

Uncaught TypeError: Cannot read property 'value' of undefined

I guess there is a problem with a template.