Pass a datetime from javascript to c# (Controller)

Try to use toISOString(). It returns string in ISO8601 format.

GET method

javascript

$.get('/example/doGet?date=' + new Date().toISOString(), function (result) {
    console.log(result);
});

c#

[HttpGet]
public JsonResult DoGet(DateTime date)
{
    return Json(date.ToString(), JsonRequestBehavior.AllowGet);
}

POST method

javascript

$.post('/example/do', { date: date.toISOString() }, function (result) {
    console.log(result);
});

c#

[HttpPost]
public JsonResult Do(DateTime date)
{
     return Json(date.ToString());
}

The following format should work:

$.ajax({
    type: "POST",
    url: "@Url.Action("refresh", "group")",
    contentType: "application/json; charset=utf-8",
    data: JSON.stringify({ 
        myDate: '2011-04-02 17:15:45'
    }),
    success: function (result) {
        //do something
    },
    error: function (req, status, error) {
        //error                        
    }
});

There is a toJSON() method in javascript returns a string representation of the Date object. toJSON() is IE8+ and toISOString() is IE9+. Both results in YYYY-MM-DDTHH:mm:ss.sssZ format.

var date = new Date();    
    $.ajax(
       {
           type: "POST",
           url: "/Group/Refresh",
           contentType: "application/json; charset=utf-8",
           data: "{ 'MyDate': " + date.toJSON() + " }",
           success: function (result) {
               //do something
           },
           error: function (req, status, error) {
               //error                        
           }
       });