Body tag class value not changing after the first browser page load

Hello and thanks for reviewing my question.

My issue involves adding unique values to the body tag's class attribute. Now, I am following tips and advice from Dustin Miller in his article: Multiple Sites with Varying Designs in a Single CSS File  which will give you the background to why and what I am doing here, see link below.

www.nothingbutsharepoint.com/sites/eusp/pages/multiple-sites-with-varying-designs-in-a-single-css-file.aspx

This situation involves Sharepoint 2010 in an IE 8 enviroment. The problem I am having is that when one calls up the page the first time the expected changes to the class attribute value appears but,when I refresh or navigate around from that point on the body class attribute doesn't.

From all best observations my function gets called but the changes never happen and I cannot figure out where the blame lies IE or  SharePoint( or with the programmer, right?)  I've gone through every possible iteration of code placement in a Master Page and still get the same results. 

Either way you look at it, it is this call: _spBodyOnLoadFunctionNames.push("speBodyClasses");

and this is the function code:

   function speBodyClasses(){ 
       var  siteColClass =  
                'sitecol' +  
                _spPageContextInfo 
                    .siteServerRelativeUrl 
                        .replace(/\//g, "-") 
                        .toLowerCase() 
        ; 
       var  siteClass =  
                'site' +  
                _spPageContextInfo 
                    .webServerRelativeUrl 
                        .replace(/\//g, "-") 
                        .toLowerCase() 
        ; 
        document.body.className = document.body.className + ' ' + siteColClass + ' ' + siteClass; 
    }