function updatediv(url, target) {
document.getElementById(target).style.display="block";
if(!isBadIE()){
document.getElementById(target).style.marginTop=-20;
}
    if (window.XMLHttpRequest) {
        req = new XMLHttpRequest();
        req.onreadystatechange = function() {ajaxDone(target);};
        req.open("GET", url, true);
        req.send(null);
    } else if (window.ActiveXObject) {
        req = new ActiveXObject("Microsoft.XMLHTTP");
        if (req) {
            req.onreadystatechange = function() {ajaxDone(target);};
            req.open("GET", url, true);
            req.send();
        }
    }
}    
function ajaxDone(target) {
    if (req.readyState == 4) {     // only if req is "loaded"
        if (req.status == 200) {         // only if "OK"
            results = req.responseText;
            document.getElementById(target).innerHTML = results;
        } else {
            document.getElementById(target).innerHTML="ajax error:\n" +   req.statusText;
        }
    }
}
function ajax_switch(url,target){
    if (document.getElementById(target).innerHTML != ''){
        document.getElementById(target).innerHTML = '';
    }else{
        updatediv(url,target);
    }
}


function isBadIE(){
  var ret = false;
  var ver = getInternetExplorerVersion();
  if ( ver > -1 )  {
    if ( ver >= 8.0 ) 
      ret = true
    else
      ret = false;
  }
  return( ret );
}


function getInternetExplorerVersion(){
  var rv = -1; 
  if (navigator.appName == 'Microsoft Internet Explorer')  {
    var ua = navigator.userAgent;
    var re  = new RegExp("MSIE ([0-9]{1,}[\.0-9]{0,})");
    if (re.exec(ua) != null)
      rv = parseFloat( RegExp.$1 );
  }
  return rv;
}

//usage:     updatediv ('getCSS.php?a=someValue', 'divID');