Quick Tip – Converting JSON Serialized .NET DateTime to JavaScript Date

October 17, 2011

one comment

Quick Tip – Converting JSON Serialized .NET DateTime to JavaScript Date

When you are using the controller JSON method in ASP.NET MVC or scriptable WCF services you sometimes have to serialize a .NET DateTime property. The DataContractJsonSerializer will serialize it into the following format:


This format indicate to the client side parsers that the data fragment that was sent is a date representation.

But how can you convert it to a JavaScript Date object?

There are a few methods:

  • “Brutal Force”: Extract the number using regular expression or substring functions and pass it to the Date object which get the time in milliseconds in its constructor:

    var date = new Date(1235398665390);

  • Server Side Approach: Send to the client side not a .NET DateTime but the total milliseconds and then use the same constructor from the previous bullet. You should pay attention that JavaScript’s base date is 1/1/1970. The following code can help:

    var baseDate = new DateTime(1970, 1, 1); 
    var currentDate = DateTime.Now.ToUniversalTime(); 
    TimeSpan ts = new TimeSpan(dcurrentDate.Ticks - baseDate.Ticks); 
    return ts.TotalMilliseconds;

  • The Eval Way: on the client side use the eval function to evaluate and create the Date object:

    var date = eval("new " + dateFromTheServer.slice(1, -1));

    Where the dateFromTheServer is in the format which was presented at the top of the post.

There are probably other ways which can help you. What is your way?

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one comment

  1. Paul DelcoglianoOctober 17, 2011 ב 19:07

    Hi Gil,

    On the client-side, I use code like this to create the date object…

    var d = new Date(parseInt(valueToFormat.substr(6)));

    where valueToFormat is in the format at the top of your post.