用户登录后如何显示计时器？

Question

I want to show timer after user login here is code :

Demo : Fiddle

function startTimer_session()
{   
    var today = new Date();            
    var h=today.getHours() - login.getHours();
    var m=today.getMinutes() - login.getMinutes();
    var s=today.getSeconds() - login.getSeconds();
    // add a zero in front of numbers<10
    h=checkTime(h);
    m=checkTime(m);
    s=checkTime(s);
    $('#user-timer').html(h+":"+m+":"+s);
    timer=setTimeout(function(){startTimer_session()},1000);
}

but it does not show properly, why?

Answer 1

The problem is that today.getSeconds is less that login.getSeconds.

You need to do the subtraction on the full date and then take the parts.

The smallest change is:

    var today = new Date(); 
    var d = new Date(today - login);
    var h = d.getHours();
    var m = d.getMinutes();
    var s = d.getSeconds();

Or use the date formatting that Satpal showed