function initRequest() {
	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');
        http_request = false;
    }
    return http_request

}

function sendRequest(http_request,params,isasync) {
    var url = url_interface;

    http_request.open('POST', url, isasync);
    http_request.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
    http_request.send(params);
}

function makeRequest(params,callback,isasync) {
	var http_request = initRequest();
	
	// -- set to asyncronous unless turned off
	if (isasync != false) {
		isasync = true;
	}
				
    http_request.onreadystatechange = function() { processResponse(http_request,callback); };
	sendRequest(http_request,params,isasync);
	
	// -- if syncronous, process now
	if  (isasync == false) {
		processResponse(http_request,callback);
	}
}

	
function processResponse(http_request,callback) {

    if (http_request.readyState == 4) {
        if (http_request.status == 200) {     
	    	callback(http_request);   
        } else {
            alert('There was a problem with the request.');
        }
    }

}