/**
 * Ajax call function
 * @param url
 * @param callback function
 */
function ajaxCall(url, callback) {

	    var http_request = false;

        if (window.XMLHttpRequest) { // Mozilla, Safari, ...
            http_request = new XMLHttpRequest();
            if (http_request.overrideMimeType) {
                http_request.overrideMimeType('text/xml');
                // See note below about this line
            }
        } else if (window.ActiveXObject) { // IE
            try {
                http_request = new ActiveXObject("Msxml2.XMLHTTP");
            } catch (e) {
                try {
                    http_request = new ActiveXObject("Microsoft.XMLHTTP");
                } catch (e) {}
            }
        }

        if (!http_request) {
            alert('Giving up :( Cannot create an XMLHTTP instance');
            return false;
        }
        http_request.onreadystatechange = function() { eval(callback);  };
        http_request.open('GET', url, true);
        http_request.send(null);


}

function handleResponse(http_request) {
	if (http_request.readyState == 4) {
	    // everything is good, the response is received
	    // do nothing this time

	} else {
    	// still not ready
    	//alert('there was a problem saving');
	}

}