Date: 2017feb20 Platform: web Keywords: html5 Q. Why is my [DOCTYPE html] page not working? A. The most common reason is missing 'px'. Older html/css assumed pixels when the unit was missing.

<style> .something { width: 100; } /* wrong */ </style>

<style> .something { width: 100px; } /* right */ </style>

Same with javaScript.

<script> node.style.left = 100; // wrong </script>

<script> node.style.left = '100px'; // right </script>

Another issue is 100% height pages not being full height. http://www.tutwow.com/htmlcss/quick-tip-css-100-height/