// open popup extra information
	function openExtra(file,popName) { 
		var w = screen.availWidth;
		var h = screen.availHeight;
		var popW = 425, popH = 585 ;
		var leftPos = (w-popW)/2, topPos = (h-popH)/2; 
 		open(file,popName,'width=' + popW + ',height=' + popH + ',top=' + topPos + ',left=' + leftPos +',toolbar=0,directories=0,status=0,menubar=0,resizable=0,scrollbars=1'); 
	}

	// gets cookie with given name
	function getCookie(NameOfCookie){
	    if (document.cookie.length > 0) {              
	    begin = document.cookie.indexOf(NameOfCookie+"=");       
	    if (begin != -1) {           
	      begin += NameOfCookie.length+1;       
	      end = document.cookie.indexOf(";", begin);
	      if (end == -1) end = document.cookie.length;
	        return unescape(document.cookie.substring(begin, end));
	    } 
	  }
	  return null;
	}

	// sets cookie with given name, value and expire date
	function setCookie(NameOfCookie, value, expiredays) {
	//var ExpireDate = new Date ();
	//ExpireDate.setTime(ExpireDate.getTime() + (expiredays * 24 * 3600 * 1000));
	
	  document.cookie = NameOfCookie + "=" + escape(value)
	  /* + 
	  ((expiredays == null) ? "" : ";
	   expires=" + ExpireDate.toGMTString());
	   */
	}