javascript: format time show rectime record time

gistfile1

function record_time(startTime) {
	var secs = Math.round(((new Date()).getTime() - startTime)/1000);
	if(secs === 0) return 1;
	var str = "",
		hr  = Math.floor(secs / 3600),
		min = Math.floor((secs - (hr * 3600))/60),
		sec = secs - (hr * 3600) - (min * 60);	
	if(hr>0) { str  += hr  + "h:"; }
	if(min>0) { str += min + "mn:"; }
	if(sec>0) { str += sec + "s"; }	

	return str;
}