function Is(){	var agt=navigator.userAgent.toLowerCase();	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.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))}