function addEvent(elm, evType, fn, useCapture)
// cross-browser event handling for IE5+, NS6+ and Mozilla/Gecko
// By Scott Andrew
{
    if(elm.addEventListener) {
        elm.addEventListener(evType, fn, useCapture);
    } else if (elm.attachEvent) {
        var r = elm.attachEvent('on' + evType, fn);
    } else {
        elm['on' + evType] = fn;
    }
}