function vote(challenge, user, photo, ip, id) {
	data = 'challenge='+encodeURIComponent(challenge)+
			'&user='+encodeURIComponent(user)+
			'&photo='+encodeURIComponent(photo) +
			'&ip='+encodeURIComponent(ip);
	var response = xml_request('doVote.php',data);
	if(response != 1) {
		window.location = 'http://www.photochallenge.net/';
	} else {
		if(id == 'p1') {
			document.getElementById('vote1').innerHTML = '<img src="imgs/green.jpg" alt="You voted for this photo." />';
			document.getElementById('vote2').innerHTML = '<img src="imgs/red.jpg" alt="You did not vote for this photo." />';
		} else {
			document.getElementById('vote2').innerHTML = '<img src="imgs/green.jpg" alt="You voted for this photo." />';
			document.getElementById('vote1').innerHTML = '<img src="imgs/red.jpg" alt="You did not vote for this photo." />';
		}
	}
}


function xml_http_request_object() {
    var req = false;
    try {
      req = new ActiveXObject("Msxml2.XMLHTTP");
    } catch (e) {
      try {
        req = new ActiveXObject("Microsoft.XMLHTTP");
      } catch (E) {
        req = false;
      }
    }

    if (!req && typeof XMLHttpRequest!='undefined') {
      req = new XMLHttpRequest();
    }
    
    return req;
}

function xml_request(url, data) {
    req = xml_http_request_object();
    req.open("POST", url, false);
    req.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
    req.send(data);
    var response = req.responseText;
    return response;
}