function GetXmlHttp()
{
   if(window.XMLHttpRequest)
   {
      var xmlObj = new XMLHttpRequest();
   } 
   else 
   {
   var xmlObj = new ActiveXObject("MSXML2.XMLHTTP.3.0");
   if (xmlObj==null){
      var MSXML = ['Microsoft.XMLHTTP', 'MSXML2.XMLHTTP.5.0', 'MSXML2.XMLHTTP.4.0', 'MSXML2.XMLHTTP.3.0', 'MSXML2.XMLHTTP'];
      for(var n = 0; n < MSXML.length; n++)
      {
         try
         {
            var xmlObj = new ActiveXObject(MSXML[n]);        
            break;
         }
         catch(e)
         {
         }
      }
   } 
  }
   return xmlObj;

}

function getAJAXReturnResult(url,dataStr)
{
	var xmlhttp=GetXmlHttp();
	var myTime = new Date(); 
	var url=url+"?thisTime="+myTime.getTime();
      xmlhttp.open('POST',url,false);
	  xmlhttp.setRequestHeader("If-Modified-Since", 0); 
      xmlhttp.setRequestHeader("Content-Length",dataStr.length); 
      xmlhttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
      xmlhttp.send(dataStr);
     var returnStr=xmlhttp.responseText;
	 return returnStr;
}

function getNextArea(varStart_end,objStr){
	var obj=eval("document.all."+varStart_end+objStr)
	objValue=obj.value;
	dataStr="result="+objValue+"&start_end="+varStart_end+"&objStr="+objStr;
	url="city_borough_postCode.asp";
	returnStr=getAJAXReturnResult(url,dataStr);
	return returnStr;
}