function postRequest(strURL) {
var xmlHttp;
if (window.XMLHttpRequest) { 
  var xmlHttp = new XMLHttpRequest();
} else if (window.ActiveXObject) {
  var xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
}

xmlHttp.open('POST', strURL, true);
xmlHttp.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
xmlHttp.onreadystatechange = function() {
  if(xmlHttp.readyState == 1 || xmlHttp.readyState == "loading") {
	document.getElementById("AJAXPORTFOLIO").innerHTML ="<img src='http://www.lesage.nl/site/images/loading.gif' border=0 alt='Bezig met laden'/>";       
  }
  if (xmlHttp.readyState == 4) {
    updatepage(xmlHttp.responseText);
   }
}
  xmlHttp.send(strURL);
}       

function updatepage(str){
document.getElementById("AJAXPORTFOLIO").innerHTML = str;}

function PortfolioNext(){
var nummer = document.getElementById('portfolioID').value;
var url="http://www.lesage.nl/site/ajax_portfolio.php?a=n&nummer="+nummer;
postRequest(url);}

function PortfolioBack(){
var nummer = document.getElementById('portfolioID').value;
var url="http://www.lesage.nl/site/ajax_portfolio.php?a=b&nummer="+nummer;
postRequest(url);}