javascript 比较时间大小

function comptime(beginTime,endTime) {

var beginTimes = beginTime.substring(0, 10).split('-');

var endTimes = endTime.substring(0, 10).split('-');

beginTime = beginTimes[1] + '-' + beginTimes[2] + '-' + beginTimes[0] + ' ' + beginTime.substring(10, 19);

endTime = endTimes[1] + '-' + endTimes[2] + '-' + endTimes[0] + ' ' + endTime.substring(10, 19);

alert(beginTime + "aaa" + endTime);

alert(Date.parse(endTime));

alert(Date.parse(beginTime));

var a = (Date.parse(endTime) - Date.parse(beginTime)) / 3600 / 1000;

if (a < 0) {

alert("endTime小!");

} else if (a > 0) {

alert("endTime大!");

} else if (a == 0) {

alert("时间相等!");

} else {

return 'exception'

}

}