function Is() {
        var agent = navigator.userAgent.toLowerCase();
        this.major = parseInt(navigator.appVersion);
        this.minor = parseFloat(navigator.appVersion);
        this.op	= (agent.indexOf("opera") != -1);
        this.ff   = (agent.indexOf("firefox") != -1);
        this.ie   = (agent.indexOf("msie") != -1);
        this.ie3  = (this.ie && (this.major == 2));
        this.ie4  = (this.ie && (this.major >= 4));
        this.win   = (agent.indexOf("win")!=-1);
        this.mac   = (agent.indexOf("mac")!=-1);
        this.unix  = (agent.indexOf("x11")!=-1);
}

var is = new Is();

if((!is.ie4 && !is.ff && !is.op) || !is.win){
        top.location.href = "/userenv.htm";
}