sfHover = function() {
  ismac = ( (navigator.userAgent.indexOf("mac") != -1) || (navigator.userAgent.indexOf("Mac") != -1) );  
//    var mac = (navigator.userAgent.indexOf("mac") != -1);
    
    if(document.all&&document.getElementById){ // ie only	
      if(d = document.getElementById("nav")) {
        var sfEls = d.getElementsByTagName("LI");
        for (var i=0; i<sfEls.length; i++) {        
	            sfEls[i].onmouseover=function() {   this.className+=" hover";    }
        	    sfEls[i].onmouseout=function() {    this.className=this.className.replace(new RegExp(" hover\\b"), "");   }
        }        
      }
    }
}