Hello everyone!
Recently I met a demand of the time required to verify input
I will write this
 
//Here is the time to check
var goTime = '2016-01-20 12:00';
//Verify time format, here I would like to use 2016-01-21 14:04
if (goTime.match(/^[0-9]{4}-[0-9]{2}-[0-9]{2} [0-9]{2}:[0-9]{2}$/) == null )//Time format
{
     alert("Time format Error");
}
//Check in time is greater than the time now
var now = new Date();//new a Date Object
//now.getTime() return UNIX time
//Date.parse will return date object
if (Date.parse(goTime) <= Date.parse(now.getTime()))
{
     alert("goTime is before now time");
}
else
{
     alert("goTime is After now time");
}

Like this should be pretty easy to understand
If you do not understand can ask me
Cheers!