// Event handler for IE/Firefox
function addEvent(elm, evType, fn, useCapture) {
    if (elm.addEventListener) {
        elm.addEventListener(evType, fn, useCapture);
        return true;        
    }
    else if (elm.attachEvent) {
        var r = elm.attachEvent('on' + evType, fn);
        return r;
    }
    else {
        elm['on' + evType] = fn;
    }
}