// Set up Event Listener

function addEvent(elm, evType, fn, useCapture) { 
    if (elm.addEventListener) {
        elm.addEventListener(evType, fn, useCapture);
        return true;
    } 
    
    if (elm.attachEvent) {
        return elm.attachEvent('on' + evType, fn);
    }
    
    elm['on' + evType] = fn;
}