Small AJAX function, only supports GET, no caching.

Small AJAX function

/**
 * Very small Ajax function.
 * 
 * Bugs: doesn't support POST, only GET.
 *
 * @param {String} url
 * @param {Function} fn
 */
function fetchXML(url, fn){
    var xmlHttp = null;
    var prop = arguments[2] || 'responseXML';
    
    if (window.XMLHttpRequest) {
        xmlHttp = new XMLHttpRequest();
    } else if (window.ActiveXObject) {
        xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
    }
    
    try {
        if (xmlHttp) {
            xmlHttp.onreadystatechange = done;
            xmlHttp.open('GET', url, true);
            xmlHttp.send('');
        }
    } catch (e) {}
    
    function done(){
        if (xmlHttp.readyState == 4 && xmlHttp.status == 200) {
            fn(xmlHttp[prop]);
        }
    }
}