if (window.ActiveXObject && !window.XMLHttpRequest) {
	window.XMLHttpRequest = function() {
		var progIds = new Array("Msxml2.XMLHTTP.6.0", "Msxml2.XMLHTTP.5.0", "Msxml2.XMLHTTP.4.0", "Msxml2.XMLHTTP.3.0", "Msxml2.XMLHTTP", "Microsoft.XMLHTTP");
		for (i in progIds) {
			try {
				return new ActiveXObject(progIds[i]);
			}
			catch(ex) {
			}
		}
		return null;
	};
}

if (!window.dimgel) { window.dimgel = {}; };

window.dimgel.ajax = {
	request: function(url, post, callback, tag, timeout, loopdelay) {
		if (!window.XMLHttpRequest) {
			callback(null, tag, -1, 'Not supported by browser.', null);
			return null;
		}
		var id = ++this._lastid;
		var r = {id: id, url: url, post: post, callback: callback, tag: tag, timeout: (timeout ? timeout : 30), loopdelay: loopdelay, xhr: null, refresh: false};
		this._requests.push(r);
		this._exec(r);
		return id;
	},
	
	changeurl: function(id, url, post) {
		var i = this._findidindex(id);
		if (i < 0) {
			return;
		}
		var r = this._requests[i];
		r.url = url;
		r.post = post;
	},
	
	refresh: function(id, force) {
		var i = this._findidindex(id);
		if (i < 0) {
			return;
		}
		var r = this._requests[i];
		if (force || r.laststate < 0) {
			this._cleanup(r);
			this._exec(r);
		}
		else {
			r.refresh = true;
		}
	},
	
	remove: function(id) {
		var i = this._findidindex(id);
		if (i < 0) {
			return;
		}
		var r = this._requests[i];
		this._requests.splice(i, 1);
		this._cleanup(r, true);
	},
	
// PRIVATE:
	
	_lastid: 0,
	_requests: new Array(),
	
	_findidindex: function(id) {
		for (var i = 0;  i < this._requests.length;  i++) {
			if (this._requests[i].id == id) {
				return i;
			}
		}
		return -1;
	},
	
	_exec: function(r) {
		var id = r.id;
		r.xhr = new XMLHttpRequest();
		r.xhr.onreadystatechange = function() { window.dimgel.ajax._onreadystatechange(id); };
		r.xhr.open(r.post ? "POST" : "GET", r.url, true);
		r.laststate = 0;
		r.timeoutid = setTimeout("window.dimgel.ajax._ontimeout(" + id + ")", r.timeout * 1000)
		r.xhr.send(r.post);
	},
	
	_cleanup: function(r, abort) {
		var ls = r.laststate;
		r.laststate = -1;
		if (r.timeoutid) {
			clearTimeout(r.timeoutid);
			r.timeoutid = null;
		}
		if (ls >= 0) {
			delete r.xhr['onreadystatechange'];
			if (abort && r.xhr.abort) {
				r.xhr.abort();
			}
			delete r['xhr'];
		}
	},

	_onreadystatechange: function(id) {
		var i = this._findidindex(id);
		if (i < 0) {
			return;
		}
		var r = this._requests[i];
		if (!r.xhr) {
			return;
		}
		var readyState = r.xhr.readyState;
		if (r.laststate < 0) {
			return;
		}
		r.laststate = r.xhr.readyState;
		if (r.xhr.readyState != 4) {
			return;
		}
		var status = r.xhr.status;
		var responseText = r.xhr.responseText;
		var responseXML = r.xhr.responseXML;
		this._cleanup(r);
		if (r.refresh) {
			r.refresh = false;
			window.dimgel.ajax.refresh(id, true);
		}
		else if (r.loopdelay > 0) {
			r.timeoutid = setTimeout("window.dimgel.ajax.refresh(" + r.id + ", false)", r.loopdelay * 1000);
		}
		else {
			this._requests.splice(i, 1);
		}
		r.callback(id, r.tag, status, responseText, responseXML);
	},
	
	_ontimeout: function(id) {
		var i = this._findidindex(id);
		if (i < 0) {
			return;
		}
		var r = this._requests[i];
		if (r.laststate < 0) {
			return;
		}
		this._cleanup(r, true);
		if (r.refresh) {
			r.refresh = false;
			window.dimgel.ajax.refresh(id, true);
		}
		else if (r.loopdelay > 0) {
			r.timeoutid = setTimeout("window.dimgel.ajax.refresh(" + r.id + ", false)", r.loopdelay * 1000);
		}
		else {
			this._requests.splice(i, 1);
		}
		r.callback(id, r.tag, -2, 'Request timed out.', null);
	}
};