var http_request;


function createXMLRequest() {
  var http_request = false;
//  alert("---- create request ----");
  if (window.XMLHttpRequest) { // Mozilla, Safari,...
    http_request = new XMLHttpRequest();
    if (http_request.overrideMimeType) {
      http_request.overrideMimeType('text/xml');
      // zu dieser Zeile siehe weiter unten
    }
  } else if (window.ActiveXObject) { // IE
    try {
      http_request = new ActiveXObject("Msxml2.XMLHTTP");
    } catch (e) {
      try {
        http_request = new ActiveXObject("Microsoft.XMLHTTP");
      } catch (e) {}
    }
  }

  if (!http_request) {
    alert('Ende :( Kann keine XMLHTTP-Instanz erzeugen');
    return false;
  }
  return http_request;
}



function createDemand(aform) {
  var str = "";
  for(var i = 0; i < aform.elements.length; i++) {
    var e = aform.elements[i];
    if(e.name) {
      if(e.type == 'radio') {
        if(e.checked == true) {
          if(i > 0)
            str += "&";
          str += e.name;
          str += "=";
          str += encodeURIComponent(e.value);
        }
      } else if(e.type == 'checkbox') {
        if(i > 0)
          str += "&";
        str += e.name;
        str += "=";
        if(e.checked)
        	str += "1";
		else
			str += "0";
      } else if(e.type == "select-multiple") {
        opt = e.options;
        for(var j = 0; j < opt.length; j++) {
          if((i > 0) || (j > 0))
            str += "&";
          str += e.name;
          str += "[" + j + "]";
          str += "=";
          if(opt[j].selected) {
            str += encodeURIComponent(opt[j].value);
          }
        }
      } else {
        if(i > 0)
          str += "&";
        str += e.name;
        str += "=";
        str += encodeURIComponent(e.value);
      }
    }
  }
  return str;
}