function BrowserCheck() { 
  var b = navigator.appName 
  if (b=="Netscape") this.b = "ns" 
  else if (b=="Microsoft Internet Explorer") this.b = "ie" 
  else this.b = b 
  this.v = parseInt(navigator.appVersion) 
  this.ns = (this.b=="ns" && this.v>=4) 
  this.ns4 = (this.b=="ns" && this.v==4) 
  this.ns5 = (this.b=="ns" && this.v==5) 
  this.ie = (this.b=="ie" && this.v>=4) 
  this.ie4 = (navigator.userAgent.indexOf('MSIE 4')>0) 
  this.ie5 = (navigator.userAgent.indexOf('MSIE 5')>0) 
  if (this.ie5) this.v = 5 
  this.min = (this.ns||this.ie) 
 } 

 var is = new BrowserCheck();

 if(is.ie || is.ns5)
  document.write("<link rel='stylesheet' type='text/css' href='styles/iestyle.css'>");
 else if(is.ns)
  document.write("<link rel='stylesheet' type='text/css' href='styles/nnstyle.css'>");