function Is () {
    // convert all characters to lowercase to simplify testing
    var agt=navigator.userAgent.toLowerCase()
	
    // *** BROWSER VERSION ***
    this.major = parseInt(navigator.appVersion)
    this.minor = parseFloat(navigator.appVersion)
	
    this.nav  = ((agt.indexOf('mozilla')!=-1) && ((agt.indexOf('spoofer')==-1)
                && (agt.indexOf('compatible') == -1)))
    this.nav2 = (this.nav && (this.major == 2))
    this.nav3 = (this.nav && (this.major == 3))
    this.nav4 = (this.nav && (this.major == 4))
    this.nav4up = this.nav && (this.major >= 4)
    this.navonly      = (this.nav && (agt.indexOf(";nav") != -1))
    this.navcrypto    = (this.nav && (this.minor >= 4.04 ))

    this.ie   = (agt.indexOf("msie") != -1)
    this.ie3  = (this.ie && (this.major == 2))
    this.ie4  = (this.ie && (this.major == 4))
    this.ie4up  = this.ie  && (this.major >= 4)

    this.opera = (agt.indexOf("opera") != -1)
}

var is = new Is();
