var thisbroswer="";
    if(document.layers){
      thisbrowser="NN4";
    }
    if(document.all){
      thisbrowser="ie";
    }
    if(!document.all && document.getElementById){
      thisbrowser="NN6";
    }
    
    var thisos="win"
    var agt=navigator.userAgent.toLowerCase();
    if (agt.indexOf("mac")!=-1)
      thisos="mac";