Why not use Javascript handlers on the body element?

Question

As an answer to the question of \'How do you automatically set the focus to a textbox when a web page loads?\', Espo suggests using

Answer 1

As a more non-javascript related answer, the presentation layer of you application could be in the form of templates or even nested templates (dreamweaver or Master Pages etc) where having specific code in the body tag may not be required or conflict with other code required when the template is "inherited"