var xmlHttp
var homeOn  = new Image();
homeOn.src  = "images/btn_home_on.gif";
var homeOff = new Image();
homeOff.src = "images/btn_home_off.gif";

function swap_image(state) {
  if (state) {
    document["homeknop"].src = homeOn.src;
  } else {
    document["homeknop"].src = homeOff.src;
  }
}

function valid(form){
  var input_boek=0;
  var input_aant=0;
  var val_str='';
  input_boek=document.bestellen.boek.value;
  input_aant=document.bestellen.aantal.value;
  val_str='bestellen.php?boek=' + input_boek;
  if (input_aant){ val_str+='&aantal=' + input_aant; }
  self.location=val_str;
}

function GetXmlHttpObject()
{
  try
    {
    // Firefox, Opera 8.0+, Safari
    xmlHttp=new XMLHttpRequest();
    }
  catch (e)
    {
    // Internet Explorer
    try
      {
      xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
      }
    catch (e)
      {
      xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
      }
    }
  return xmlHttp;
}

function stateChanged()
{
  if (xmlHttp.readyState==4)
  {
  document.getElementById("txtHint").innerHTML=xmlHttp.responseText;
  }
}

function showHint(str)
{
   var cboFirst = document.getElementById("aantal");
//   cboFirst.items.add(new listItem("First Value","5"));
//   cboFirst.items.add(new listItem("Second Value","6"));
   cboFirst.value=cboFirst.items[2].value;
/* if (str.length==0)
  {
  document.getElementById("txtHint").innerHTML="";
  return;
  }
  xmlHttp=GetXmlHttpObject()
  if (xmlHttp==null)
    {
    alert ("Your browser does not support AJAX!");
    return;
    }
  var url="gethint.asp";
  url=url+"?q="+str;
  url=url+"&sid="+Math.random();
  xmlHttp.onreadystatechange=stateChanged;
  xmlHttp.open("GET",url,true);
  xmlHttp.send(null); */
}