function PlainAjax() {

	this.timeout = 300000;

	this.requests = new Array();
	this.reqnextid = 0;

	this.request = function(paramstring, resultfunc) {
		this.cleanUpRequests();
		if (this.conftext == null || confirm(this.conftext)) {
			var request = new this.PlainAjaxRequest(this.reqnextid, paramstring, resultfunc);
			this.requests.push(request);
			if (request.autoresend != undefined && request.autoresend != null) {
				request.prepareAutoRequest();
				request.doRequest();
				setInterval(request.autoRequest, request.autoresend);
			} else {
				 request.doRequest();
			} 
			++this.reqnextid;
		}
	}

	this.cleanUpRequests = function() {
		for ( var i = 0; i < this.requests.length; ++i) {
			current = new Date().getTime();
			if (current - this.requests[i].timestamp > this.timeout)
				this.requests.splice(i, 1);
		}
	}

	this.getRequest = function(id) {
		return this.requests[this.getPos(id)];
	}

	this.delRequest = function(id) {
		this.requests.splice(this.getPos(id), 1);
	}

	this.getPos = function(id) {
		for ( var i = 0; i < this.requests.length; ++i)
			if (this.requests[i].id == id)
				return i;
		throw "Request not found";
	}

	this.PlainAjaxRequest = function(id, paramString, resultfunc) {

		this.id = id;
		this.resultfunc = resultfunc;
		this.timestamp = new Date().getTime();
		this.xmlhttp;

		this.respurl;
		this.resultloc;
		this.paramloc;
		this.autoresend;
		this.conftext;
		this.loadmsg;
		this.loadmsgloc;

		this.trimText = function(text) {
			while (text.substring(0, 1) == ' ')
				text = text.substring(1, text.length);
			while (text.substring(text.length - 1, text.length) == ' ')
				text = text.substring(0, text.length - 1);
			return text;
		}

		this.processParamString = function(paramString) {
			var pars = paramString.split(';');
			for ( var pari = 0; pari < pars.length; ++pari) {
				var parStr = pars[pari];
				var par = parStr.split(':');
				if (par.length == 2) {
					var name = this.trimText(par[0]);
					var value = this.trimText(par[1]);
					switch (name) {
						case "respurl": this.respurl = value; break; 
						case "resultloc": this.resultloc = value; break;
						case "paramloc": this.paramloc = value;	break;
						case "autoresend": this.autoresend = value; break;
						case "conftext": this.conftext = value; break;
						case "loadmsg":	this.loadmsg = value; break;
					}
				}
			}
		}

		this.processParamString(paramString);
		
		this.performAction;
		this.prepareAction = function() {
			var reqId = this.id;
			this.performAction = function() {			
				var request = window.plainajax.getRequest(reqId);	
				if (request.xmlhttp.readyState == 4 && request.xmlhttp.status == 200) {
					var resp = request.xmlhttp.responseText;
					if (request.resultloc) {
						var htmlElement = document
								.getElementById(request.resultloc);
						if (htmlElement.tagName == 'TEXTAREA') {
							htmlElement.value = resp;
						} else {
							htmlElement.innerHTML = resp;
						}
					}
					if (request.resultfunc != undefined && request.resultfunc != null) {
						request.resultfunc(resp);
					}
					
					if (request.autoresend == undefined && request.autoresend != null) {
						window.plainajax.delRequest(reqId);
					} 
				}	
			}
		}
		
		this.autoRequest;
		this.prepareAutoRequest = function() {
			var reqId = this.id;
			this.autoRequest = function() {
				var request = window.plainajax.getRequest(reqId);
				request.doRequest();
			}
		}
		
		this.doRequest = function() {		
			this.prepareAction();
			this.initXmlHttp();
			if (this.loadmsg != null) {
				var target = this.loadmsgloc == null ? this.resultloc : this.loadmsgloc;
				var targetElement = document.getElementById(target);
				if (targetElement == null)
					alert('Warning: target HTML element not found: ' + target);
				if (targetElement.tagName == 'TEXTAREA')
					targetElement.value = this.loadmsg;
				else
					targetElement.innerHTML = this.loadmsg;
			}
			this.timestamp = new Date().getTime();
			this.xmlhttp.send(querystring);
		}

		this.createUrl = function() {
			var connectchar = this.respurl.indexOf('?') != -1 ? '&' : '?';
			var url = this.respurl + connectchar + "timeStamp="
					+ this.timestamp;
			return url;
		}

		this.getFields = function() {
			var pdiv = document.getElementById(this.paramloc);
			var fieldtypes = new Array("input", "textarea", "select");
			fields = new Array();
			for (typei = 0; typei < fieldtypes.length; ++typei) {
				var fieldtype = fieldtypes[typei];
				var nodes = pdiv.getElementsByTagName(fieldtype);
				for (nodeid = 0; nodeid < nodes.length; ++nodeid) {
					var node = nodes[nodeid];
					if ((fieldtype != "input" || (fieldtype == "input"
							&& node.type != "button" && node.type != "file")
							&& ((node.type != "checkbox" && node.type != "radio") || (node.checked)))
							&& ((fieldtype == "input"
									|| fieldtype == "textarea" || fieldtype == "select") && !node.disabled))
						fields.push(node);
				}
			}
			return fields;
		}

		this.createQueryString = function() {
			querystring = '';
			if (this.paramloc != null) {
				var fields = this.getFields();
				for (i = 0; i < fields.length; ++i) {
					var node = fields[i];
					if (node.name != "" && node.type != "file")
						querystring += '&' + node.name + '='
								+ escape(node.value);
				}
			}
			return querystring;
		}

		this.initXmlHttp = function() {
			var querystring = this.createQueryString();
			this.xmlhttp = window.XMLHttpRequest ? new XMLHttpRequest() : new ActiveXObject("MSXML2.XMLHTTP.3.0");
			var method = (this.paramloc == null) ? "GET" : "POST";
			this.xmlhttp.open(method, this.createUrl(), true);
			this.xmlhttp.onreadystatechange = this.performAction;
			this.xmlhttp.setRequestHeader("Content-type",
					"application/x-www-form-urlencoded");
			this.xmlhttp.setRequestHeader("Connection", "close");
			this.xmlhttp.setRequestHeader("Content-length", querystring.length);
		}
	}
}

var plainajax = new PlainAjax();
window.plainajax = plainajax;