var http_request;

function createRequest() {

	http_request = false;

    if (window.XMLHttpRequest) { // Mozilla, Safari,...
    	http_request = new XMLHttpRequest();
    } 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('Ende :( Kann keine XMLHTTP-Instanz erzeugen');
    	return false;
    }

	return http_request;
        
}