Get Current Time from Server Side in Javascript

I am assuming this is in a web client:
You will need an API on the server that returns the server time. You will need to use a fetch(apiURL) to get the response and use it in your code. 

For node then use Aniket's answer, but use .toLocalString() or some variation of the .ToLocal[property]String methods.

var s = new Date('<%= DateTime.Now.ToString() %>');
function updateTime()
{

var labelref = document.getElementById('<%= Label1.ClientID %>');

if(labelref.innerHTML.toString() != "freetime") s = labelref.innerText;

var serverDateTime = new Date(Date.parse(s.toString()));

if ( labelref )
{

var serverMonthValue = serverDateTime.getMonth() + 1;
var serverDayValue = serverDateTime.getDate();
var serverYearValue = serverDateTime.getFullYear();
var serverHoursValue = serverDateTime.getHours();
var serverMinutesValue = serverDateTime.getMinutes();
var serverSecondsValue = serverDateTime.getSeconds();

serverSecondsValue++;

if ( serverSecondsValue >= 60 )
{
serverSecondsValue -= 60;
serverMinutesValue++;
}
if ( serverMinutesValue >= 60 )
{
serverMinutesValue -= 60;
serverHoursValue++;
}
if ( serverHoursValue >= 24 )
{
serverHoursValue -= 24;
serverDayValue++;
}

var newt= new Date(Date.parse(serverMonthValue + '/' + serverDayValue + '/' + serverYearValue + ' ' +
serverHoursValue + ':' + serverMinutesValue + ':' + serverSecondsValue));

labelref.innerHTML= newt;

}
}

window.setInterval(updateTime, 1000);