ASP/AJAX - Client Timer synchronous with Server Timer

I'm searching for an example with an client timer that ticks synchronous with 开发者_开发问答an server timer. Also there must be a button on the client side which can reset the server timer to an default value, and with this it also resets the client timer ofcourse.

I tried it myself but it seems that there is some postback delay which makes it impossible for me to make it atleast look like it goes synchronous.

I hope somebody got an example for me, the button part is really important because by pressing that button the delay comes.

Thanks in advance,

Julian

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write server offset into response like JSON or any other way and use it as parameter for next method

function getServerTime(serverOffset)
{
    var myDate=new Date();
    myDate.setDate(myDate.getTime()+(serverOffset*60*60*1000));
    return myDate;
}

this method you can call each second and put returned value where ever you want.