[wp-hackers] Write Post form validation before submit

[Malaiac]

ok, again, support may not be the right place
http://wordpress.org/support/topic/193025
'I have added a custom input (URL) to the 'Write Post' page.
I'd like to make this custom input required (not empty) and valid (URL
syntax valid) to save/submit the Post.

Is there any plugin / way to do that avoiding rude javascript inside
the post-new.php page ?'

No answer yet, anyone here using something to validate form content
before allowing an author to submit/an editor to publish ?

I saw some " class="form-required"  " in edit-form-advanced.php but no
trivial way to use them.

Malaiac