//IE
if (window.ActiveXObject) 
{
    http = new ActiveXObject("Microsoft.XMLHTTP");
}
//alternatieve browsers
else if (window.XMLHttpRequest) 
{
    http = new XMLHttpRequest();
}

function getCount()
{
  if(http) {
    place_name = document.forms[0].place_name;
  	duration = document.forms[0].duration;
  	price = document.forms[0].price;
  	
  	var regionId = place_name.options[place_name.selectedIndex].value;
  	var duration = duration.options[duration.selectedIndex].value;
    var price = price.options[price.selectedIndex].value;
    var date = document.forms[0].date.value;
    
    var url = "count.php?regionId=" + regionId +"&duration="+duration+"&price="+price+"&date="+date;
  
  	http.open('get', url,true);
    http.onreadystatechange = function() {
      if (http.readyState == 4 && http.status == 200) { 
        var response = http.responseText;
		    document.getElementById('test').innerHTML = "Er zijn "+response+" reizen gevonden. Klik op laat zien om de reizen te bekijken."; 
      }  
    }   
  http.send(null); 
  }
}