var IEversion = 0;
var NNversion = 0;

if(navigator.appName.indexOf("Microsoft") >= 0){
        if(navigator.appVersion.charAt (0)==4 ){
                if(navigator.appVersion.indexOf ("MSIE 5") != -1){
                        IEversion = 5;
                }else{
                        IEversion = 4;
                }
        }
} else {
        if(navigator.appName.indexOf("Netscape") >= 0){
                if(navigator.appVersion.charAt(0) ==4){
                        NNversion = 4;
                }else if(navigator.appVersion.charAt(0) ==5){
                        NNversion = 6;
                }
        }
}