/**
 * addEventListener
 * 
 * @author s_miki
 */
function addListener(elm, event, listener) {

	if (elm.addEventListener) {
		elm.addEventListener(event, listener, false);
	}

	else if (elm.attachEvent) {
		elm.attachEvent('on' + event, function() {
			listener.call(elm, window.event);
		});
	}

	else elm['on' + event] = function(e) {
		listener.call(elm, e || window.event);
	};
}