function checkBrowser()
{
  this.ver=navigator.appVersion
  this.dom=document.getElementById?1:0
  this.ie5=(this.ver.indexOf("MSIE 5")>-1 && this.dom)?1:0;
  this.ie4=(document.all && !this.dom)?1:0;
  this.pc=(navigator.appVersion.indexOf("Mac") == -1)
  this.iepc=(this.pc &&  (this.ie4 || this.ie5)==1)
  this.ie4mac=((!this.pc) &&  (this.ie4)==1)
  this.ns5=(this.dom && parseInt(this.ver) >= 5) ?1:0;
  this.ns5mac=((!this.pc) && (this.ns5)==1)
  this.iemac=((!this.pc) && (this.ie5 || this.ns5)==1)
  this.ns4=(document.layers && !this.dom)?1:0;
  this.bw=(this.ie5 || this.ie4 || this.ns4 || this.ns5)
  return this;
} 

bw=new checkBrowser()