var Ajax = function()
{
    var httpRequest;
    
    this.sendRequest = function (url, CallbackFunction) 
    {
        if (window.XMLHttpRequest) 
        { // Mozilla, Safari, ...
            this.httpRequest = new XMLHttpRequest();
            if (this.httpRequest.overrideMimeType) 
            {
                //this.httpRequest.overrideMimeType('text/xml');
                // See note below about this line
            }
        }
        else if (window.ActiveXObject) 
        { // IE.x
            try 
            {
                this.httpRequest = new ActiveXObject("Msxml2.XMLHTTP");
            }
            catch (e) 
            {
                try 
                {
                    this.httpRequest = new ActiveXObject("Microsoft.XMLHTTP");
                } 
                catch (e) {}
            }
        }
        if (!this.httpRequest) 
        {
            alert('Giving up :( Cannot create an XMLHTTP instance');
            return false;
        }
        var self=this;
        this.httpRequest.onreadystatechange = function()
            { 
              CallbackFunction(self.httpRequest); 
              // FIXME: timeout
            };
        this.httpRequest.open('GET', url, true);
        this.httpRequest.send( null );
    }
    
    this.getResponse = function () 
    {
        if (this.httpRequest.readyState == 4) 
        {
            if (this.httpRequest.status == 200) 
            {
                ct = this.httpRequest.getResponseHeader('Content-Type');
                if (ct && ct.indexOf('xml') != -1)
                {
                    return this.httpRequest.responseXML;
                }
                else
                {
                    if (ct.indexOf('json')!=-1)
                    {
                        var json = new JSON();
                        return json.decode(this.httpRequest.responseText);
                    }
                    else
                    {
                        return this.httpRequest.responseText;
                    }
                }
            } 
            else 
            {
                alert('There was a problem with the request.');
            }
        }
        else
        {
            return 0;
        }
    }
}