http_request = false;

function makeRequest(uurl,call_function) {

    http_request = false;

    if (window.XMLHttpRequest) { // Mozilla, Safari,...
        http_request = new XMLHttpRequest();
        if (http_request.overrideMimeType) {
            http_request.overrideMimeType('text/xml');
        }
    } 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 an XMLHTTP instance');
        return false;
    }
    http_request.onreadystatechange = call_function;
    http_request.open('GET', uurl, true);
    http_request.send(null);

}