Very simple javascript & CSS fixed header on scroll down based on an element's height (IE 6+ minimum): CodePen demo.

Pure vanilla javascript with no dependencies. Add a "fixed" class on an identified div element (#header) which allow to fix it when visitors scroll down on a web page. Calculations are made automaticaly based on the height of this #header. Simply copy/past: you just need to add a CSS declaration into your styles file (i.e.: .fixed{position:fixed}).

<div class="header-outer" id="header-outer">
  <div class="header-inner" id="header">
    Header
  </div>
</div>

Note: IDs header-outer & header are needed (can be changed for other identifiants, see options below).

down: distance in pixels from the top of the page where to apply the fixed element. Default: the #header's height.

up: distance in pixels from the top of the page where to stop the fixed element. Default: the #header's height.

delay: timeout in milliseconds. Default: 70.

Call this script with its function fixednav() and set options as needed:

fixednav({id:"inner-id", outer:"outer-id", distance:40, down:50, up:200, delay:70});

id: ID of the inner element of the header.

outer: ID of the outer element of the header.

distance: (optional) distance in pixel from the top of the browser's window where to apply the fixed position. Default: the menu element height.

down: (optional) additional down distance in pixel when to apply the fixed position. Default: 0.

up: (optional) additional up distance in pixel when to remove the fixed position. Default: 0.

delay: (optional) delay in ms. Default: 70 ms.

Check out: this online demo (new version).

Check out: this online demo (old version).