The Web Developer's Ten Commandments

  Thou shalt validate
  thy HTML and CSS

Thou shalt not trust in
default value settings

Thou shalt not mix
    content with presentation

Thou shalt not annoy thy
fellow man with jerking
and blinking images

  Thou shalt make thy code clear
to thy fellow man

  Thou shalt not leave
 loose ends in thy code

Thou shalt not mix zero
with null, lest grievous
harm befall thy code

Thou shalt always
keep it simple

Thou shalt not use images

 Thou shalt respect thy
user with proper messages