function lib_bcheck(){ 

  this.ver=navigator.appVersion;

  this.agent=navigator.userAgent;

  this.dom=document.getElementById?1:0;

  this.opera5=(document.all && !document.styleSheets);

  this.ie5=(this.ver.indexOf("MSIE 5")>-1 && this.dom && !this.opera5)?1:0; 

  this.ie6=(this.ver.indexOf("MSIE 6")>-1 && this.dom && !this.opera5)?1:0;

  this.ie56=(document.createElement && this.dom && !this.opera5)?1:0;

  this.ie4=(document.all && !this.dom && !this.opera5)?1:0;

  this.ie=this.ie4||this.ie5||this.ie6 || this.ie56;

  this.mac=this.agent.indexOf("Mac")>-1;

  this.ns6=(this.dom && document.createElement) ?1:0; // gilt auch fuer mozilla

  this.ns4=(document.layers && !this.dom)?1:0;

  this.bw=(this.ie56 || this.ie6||this.ie5||this.ie4||this.ns4||this.ns6||this.opera5);

  return this;

}

is=new lib_bcheck(); //Browsercheck object