function Is() { //browser leválogatás
    agent  = navigator.userAgent.toLowerCase();
    this.major = parseInt(navigator.appVersion);
    this.minor = parseFloat(navigator.appVersion);
    this.ns    = ((agent.indexOf('mozilla')   !=   -1) &&
                 ((agent.indexOf('spoofer')   ==   -1) &&
                 (agent.indexOf('compatible') ==   -1)));
    this.ns4   = (this.ns && (this.major      <=    4)&&
                 (this.minor                  <   5));
    this.ns6    = (this.ns && (this.major     >=    5));
    this.ie    = (agent.indexOf("msie")       !=   -1);
    this.ie4   = (this.ie && (this.major      ==    4) &&
                 (agent.indexOf("msie 5.0")   ==   -1));
    this.ie5   = (this.ie && (this.major      ==    4) &&
                 (agent.indexOf("msie 5.0")   !=   -1));
    this.iframe =  (this.ie || this.ns6) ;
}

var is = new Is();