function Ajax() {}

Ajax.debug = false;

//Ajax.okMessage = '[OK]';

Ajax.isOk = function(str) {
    return (str == '[OK]') || (str == "'[OK]'");
}

Ajax.doPostQuery = function(url, h, onfinish, isSync) {
    var instance = new Ajax();
    instance.getQuery = '';
    instance.postQuery = Ajax.composeQuery(h)
    instance.contentType = 'application/x-www-form-urlencoded';
    instance.onfinish = onfinish;
    instance.send(url, isSync);
}

Ajax.doGetQuery = function(url, h, onfinish, isSync) {
    var instance = new Ajax();
    instance.getQuery = '?' + Ajax.composeQuery(h);
    instance.onfinish = onfinish;
    instance.send(url, isSync);
}

/* impl */

Ajax.prototype.send = function(url, isSync) {
    try {
        var me = this;

        this.req = Ajax.getHttpRequest();
        this.req.onreadystatechange = function() { Ajax.waiting(me); }
        this.req.open(this.postQuery ? 'POST' : 'GET', url + this.getQuery, !isSync);
        if (this.contentType) {
            this.req.setRequestHeader('Content-Type',this.contentType);
        }
        this.req.send(this.postQuery);
    } catch (err) {
            Ajax.onerror('can not create newRequest - ' + err);
    }
}

Ajax.waiting = function(me) {
    try {
        var httpStatus = me.req.status;
        var readyState = me.req.readyState; // IE say here "unknown error" :-/
    } catch(e) {
        return;
    }
    if (readyState == 4) {
        if (httpStatus == 200 || httpStatus == 0){
            if (Ajax.debug) Debug.show('httpStatus = ' + httpStatus + '; response: ' + me.req.responseText);
            //me.onfinish( Ajax.responsePostprocess(me.req.responseText) );
            me.onfinish(me.req.responseText);
        } else {
            Ajax.onerror('status ' + httpStatus + '; txt = ' + me.req.responseText);
        }
    }
}

Ajax.composeQuery = function(hParams) {
    var query = '';
    for (var param in hParams) {
        query +=
            param + '=' +
            //hParams[param].replace(new RegExp('\\+','g'), '%2B') + '&';
            hParams[param] + '&';
    }
    return query;
}

Ajax.getHttpRequest = function() {
    if (window.XMLHttpRequest) {
        return new XMLHttpRequest();
    } else if (window.ActiveXObject) {
        return new ActiveXObject("Microsoft.XMLHTTP");
    } else {
        Ajax.error('Can not create HttpRequest. May be used very old browser.');
    }
}

Ajax.onerror = function(err) {
    if (!err) err = '';
    document.writeln('AJAX ERROR: ' + err);
}

Ajax.test = function() {
    Ajax.getHttpRequest();
}

Ajax.test();

function form2hash(form) {
    var hRes = {};
    for (var key in form.elements) {
        var elem = form.elements[key];
        if (!elem || !elem.name) {
            continue;
        } else if (typeof elem.value != 'undefined') {
            hRes[elem.name] = elem.value;
        } else if (typeof elem.innerHTML  != 'undefined') {
            hRes[elem.name] = elem.innerHTML;
        }
    }
    return hRes;
}