var xmlHttp = null;
var wert_global = "";
function aufdenmerkzettel(wert) {
  wert_global = wert;
  if (window.ActiveXObject) {
    try {
      xmlHttp= new ActiveXObject("Msxml2.XMLHTTP");
    } catch (e) {
      try {
        xmlHttp= new ActiveXObject("Microsoft.XMLHTTP");
      } catch (e) {
      }
    }
  } else if (window.XMLHttpRequest) {
    try {
      xmlHttp= new XMLHttpRequest();
    } catch (e) {
    }
  }

  if (xmlHttp) {
    xmlHttp.open('GET', 'scripts/ajax/merkzettel.php?isbn=' + wert, true);
    xmlHttp.onreadystatechange = daten;
    xmlHttp.send(null);
  }
}

var text = '';
function daten() {


    if (xmlHttp.readyState == 4) {
    	controller = xmlHttp.responseText;
    	if(controller == 'added') {
    	  document.getElementById(wert_global).style.backgroundImage = 'url(pics/merk_del.gif)';
    	  document.getElementById(wert_global).innerHTML = 'Vom Merkzettel löschen';
      }
      if(controller == 'del') {
    	  document.getElementById(wert_global).style.backgroundImage = 'url(pics/merk_add.gif)';
    	  document.getElementById(wert_global).innerHTML = 'Auf den Merkzettel';
      }
    }
}