function simpleGETRequest(url, callback) {
    var http_request = false;
    if (window.XMLHttpRequest) { // Mozilla, Safari,...
	http_request = new XMLHttpRequest();
	if (http_request.overrideMimeType) {
	    // set type accordingly to anticipated content type
	    http_request.overrideMimeType('text/html');
	}
    } 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('Cannot create XMLHTTP instance');
	return false;
    }
    http_request.onreadystatechange = function() { 
	if (http_request.readyState == 4) { 
	    callback(http_request.status, http_request.responseText); 
	}
    };
    http_request.open('GET', url, true);
    http_request.send(null);
}