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