ajax = Class.create();
ajax.prototype = {
    initialize: function(url, options) {
        this.transport = this.getTransport();
        this.postBody = options.postBody || '';
        this.method = options.method || 'post';
        this.onComplete = options.onComplete || null;
        this.update = $(options.update) || null;
        this.request(url);
    },

    request: function(url) {
        this.transport.open(this.method, url, true);
        this.transport.onreadystatechange = this.onStateChange.bind(this);
        if (this.method == 'post') {
            this.transport.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
            if (this.transport.overrideMimeType) this.transport.setRequestHeader('Connection', 'close');
        }
        this.spinner = new ActivityIndicator("body", {image: "/gambana-images/spinner_big.gif"});
        this.transport.send(this.postBody);
    },

    onStateChange: function() {
        if (this.transport.readyState == 4 && this.transport.status == 200) {
            this.spinner.destroy();
            if (this.onComplete)
                setTimeout(function() {
                    this.onComplete(this.transport);
                }.bind(this), 10);
            if (this.update)
                setTimeout(function() {
                    this.update.innerHTML = this.transport.responseText;
                }.bind(this), 10);
            this.transport.onreadystatechange = function() {
            };
        }
    },

    getTransport: function() {
        if (window.ActiveXObject) return new ActiveXObject('Microsoft.XMLHTTP');
        else if (window.XMLHttpRequest) return new XMLHttpRequest();
        else return false;
    }
};