JavaScript GetDate无法跨区域使用

Question

I have some JS code which takes in the client's date/time and passes it to the server like so:

function SetPostbackValues() {
        //Function that gets the client machine datetime and stores it in a hidden field
        // so it may be used in code behind.
        var date = new Date();
        var day = date.getDate();        // yields day
        if (day < 10)
            day = '0' + day;
        var month = date.getMonth() + 1;    // yields month
        if (month < 10)
            month = '0' + month;
        var year = date.getFullYear();  // yields year
        var hour = date.getHours();     // yields hours
        if (hour < 10)
            hour = '0' + hour;
        var minute = date.getMinutes(); // yields minutes
        if (minute < 10)
            minute = '0' + minute;
        var second = date.getSeconds(); // yields seconds
        if (second < 10)
            second = '0' + second;

        var time = day + "/" + month + "/" + year + " " + hour + ':' + minute + ':' + second;
        var hiddenControl = '<%= hfDateTime.ClientID %>';
        document.getElementById(hiddenControl).value = time;
    }

My problem is that the code works fine when the client time zone settings are set to a UK standard, dd/MM/yyyy but when a US client connects, the conversion to DateTime throws an error saying it is not of the right format.

Because I am getting each month, day, year separately and combining them, I do not understand why it does not work across different zone settings.

The error occurs when trying to insert datetime into SQL:

using (SqlCommand cmd = new SqlCommand("Remove", con))
                    {
                        string test = (this.Master.FindControl("hfDateTime") as HiddenField).Value;
                        cmd.CommandType = CommandType.StoredProcedure;
                        cmd.Parameters.Add("@RemovalDate", SqlDbType.DateTime).Value = (this.Master.FindControl("hfDateTime") as HiddenField).Value; //Get the client's datetime.
                        con.Open();
                        insertedRecordID = (int)cmd.ExecuteScalar();
                    }

The error is {"Failed to convert parameter value from a String to a DateTime."}

The value of test is: "19/02/2016 10:55:45" which does not look wrong to me.

Answer 1

I think you should use this:

function SetPostbackValues() {
    var date = new Date();        
    var hiddenControl = '<%= hfDateTime.ClientID %>';
    document.getElementById(hiddenControl).value = date.toISOString();
}

And change codebehind to

cmd.Parameters.Add("@RemovalDate", SqlDbType.DateTime).Value = DateTime.Parse((this.Master.FindControl("hfDateTime") as HiddenField).Value);

Answer 2

It might be easier to use (new Date()).getTime() avoiding the different datetime formats. Note that C# DateTime has a different base and scale for its constructor than Javascript.

Depending on whether you need UTC or local time, subtract datevalue.getTimezoneOffset() * 60000 .