function getXMLHTTPRequest() {
  try {
    req = new XMLHttpRequest();
  } 
  catch(err1) {
    try {
      req = new ActiveXObject("Msxml2.XMLHTTP");
    } catch (err2) {
      try {
        req = new ActiveXObject("Microsoft.XMLHTTP");
      } catch (err3) {
        req = false;
      }
    }
  }
return req;
}

var http = getXMLHTTPRequest();

function getColorOpts() {
  var url = './includes/colors.php';
  var index = document.getElementById('szid').selectedIndex;
  var size_sel = document.getElementById('szid').options[index].value;
  var syid = document.getElementById('syid').value;
  var itid = document.getElementById('itid').value;
  var id=parseInt(Math.random()*99999999);
  var modurl = url+"?szid="+size_sel+"&syid="+syid+"&itid="+itid+"&id="+id;
  http.open("GET", modurl, true);
  http.onreadystatechange = useHttpResponse;
  http.send(null);
}

function useHttpResponse() {
  if (http.readyState == 4) {
    if (http.status == 200) {
      var mytext = http.responseText;
      document.getElementById('colorField').innerHTML = mytext;
    } else {
      document.getElementById('colorField').innerHTML = "";
    }
  }
}

function showQty() {
  var url = './includes/quantity.php';
  var id=parseInt(Math.random()*99999999);
  var modurl = url+"?id="+id;
  http.open("GET", modurl, true);
  http.onreadystatechange = useHttpResponse2;
  http.send(null);
}

function useHttpResponse2() {
  if (http.readyState == 4) {
    if (http.status == 200) {
      var mytext = http.responseText;
      document.getElementById('qtyField').innerHTML = mytext;
    } else {
      document.getElementById('qtyField').innerHTML = "";
    }
  }
}