onLoad

I recently converted a page to xhtml, I inserted the xhtml transitional DTD,
sent it to the validator and it failed, Why? because I had a javascript
event handler ( onLoad) in the body tag.
Now I asked around and was told that it is because xhtml is case sensitive
the onLoad event handler should be onload, i.e. lowercase l.
I argued this isn't correct because the event handler is a javascript event
handler, and it should be formatted with the uppercase L because js is case
sensitive as well.
So we now got the HTML coders who say the tag is theirs and should be their
way, and the scripters who say the opposite.
Does anyone know who is correct here?
I have read back and according to Netscape's documentation, it should be
onLoad, but in HTML 4.01 it is onload.
I know it sounds trivial, but try telling that to the W3C XHTML validator