GetWordCount() from http://www.n7studios.co.uk/2010/03/01/ckeditor-word-count-plugin/

GetWordCount

    /**
    * Takes the given HTML data, replaces all its HTML tags with nothing, splits the result by spaces, 
    * and outputs the array length i.e. number of words.
    * 
    * @param string htmlData HTML Data
    * @return int Word Count
    */
    function GetWordCount(htmlData) {
        return htmlData.replace(/<(?:.|\s)*?>/g, '').split(' ').length;    
    }