function browserCheck()
{
    var agent = navigator.userAgent.toLowerCase();

    this.IE = false;
    this.NS = false;

    if (agent.indexOf("msie") >= 0)
    {
        this.IE = true;
        this.version = parseInt(agent.appVersion);
        return;
    }

    if (agent.indexOf("netscape") >= 0 || agent.indexOf("mozilla") >= 0)
    {
        this.NS = true;
        this.version = parseInt(agent.appVersion);
        return;
    }
    
} // browserCheck

is = new browserCheck();