http://stackoverflow.com/questions/1229333/how-to-implement-reuseable-html-navigation-menus

<script type="text/javascript" src="includes.js"></script>

Then you’ll create a document called includes.js.

At the top of this document you’ll declare your navigation variable:

var navigation  = new Array();  // This is for the navigation.

Then a little ways down in that same document you need to actually outline your navigation code (the line numbers in the square brackets are crucial – keep them in order and start with 0 – you cannot have line breaks in this code so every line of code has to be a new line):

// ==================== Navigation ==================== //
navigation[0]   = '<div id="tab_navigation">';
navigation[1]   = '<ul id="dropline">';
navigation[2]   = '<li><a href="index.htm"><b>Home</b></a></li>';
navigation[3]   = '<li><a href="about_us.htm"><b>About Us</b></a></li>';
navigation[4]   = '</ul>';
navigation[5]   = '</div><!-- Close TAB NAVIGATION -->';

Then a little ways after that you’ll actually insert the javascript that will put that code into your page (it doesn’t actually put it there but rather makes it accessible in the page without actually altering the code of the .htm page – so if you view source you’ll see the reference to the code not the code itself).

function show(i)
 {
  for (x in i)
  {
   document.write(i[x]+'\n')
  }
 }

Finally – in your .htm document, say for your index.htm page, you’ll replace your navigation code (that you put in the above block called navigation) with this:

<script type="text/javascript">show(navigation);</script>

Where that name after SHOW and in the parenthesis is the name of your variable (declared earlier).