var IE = false;
var NS = false;
var FX = false
var OP = false;
var DHTML_support = false;
var navigatorVersion = 0;
checkBrowser();

function checkBrowser() {
    var userAgent = navigator.userAgent;
    if (userAgent.indexOf('Netscape') != -1) {
        navigatorVersion = parseFloat(userAgent.substring(userAgent.indexOf('Netscape') + 9, userAgent.length));
        NS = true;
    }
    else if (userAgent.indexOf('MSIE') != -1) {
        navigatorVersion = parseFloat(userAgent.substring(userAgent.indexOf('MSIE') + 4, userAgent.length));
        IE = true;
        DHTML_support = navigatorVersion >= 5;
    }
    else if (userAgent.indexOf('Firefox') != -1) {
        navigatorVersion = parseFloat(userAgent.substring(userAgent.indexOf('Firefox') + 1, userAgent.length));
        FX = true;
    }
    else if (userAgent.indexOf('Opera') != -1) {
        navigatorVersion = parseFloat(userAgent.substring(userAgent.indexOf('Opera') + 1, userAgent.length));
        OP = true;
    }

}