js 时间比对

var startDate = "2011-02-14 11:12:21";
var endDate ="2011-01-14 11:12:31";
var arr=startDate.split("-");
var arr2=endDate.split("-");
var time1=Date.parse(arr[1]+"/"+arr[2]+"/"+arr[0]);
var time2 =Date.parse(arr2[1]+"/"+arr2[2]+"/"+arr2[0]);
if(time1>time2){
alert("起始时间不能大于结束时间");
return;
}