Untitled

Validating parts of a date/time that is entered as separate fields
TextBox1.Text = "is a date value";
TextBox2.Text = "is hour of a datetime";
TextBox3.Text = "is minutes of a datetime";

protected void CustomValidator1_ServerValidate(object source, ServerValidateEventArgs args)
{
    DateTime dateOutput = default(DateTime);
    DateTime.TryParse(TextBox1.Text, out dateOutput);

    if (dateOutput != DateTime.MinValue)
    {
        string dateString = string.Empty;

        if (TextBox2.Text == string.Empty && TextBox3.Text == string.Empty)
            dateString = dateString = string.Format("{0} {1}:{2}", TextBox1.Text, DateTime.Now.Hour, DateTime.Now.Minute);
        DateTime.TryParse(dateString, out dateOutput);
    }
    args.IsValid = (dateOutput != DateTime.MinValue);
}

<script type="text/javascript">
  function validateMyForm(){
    //write code to validate user input.
    if(!succeed)
       return false;
    return true;
  }
</script>
<form id="form1" runat="server" onsubmit="return validateMyForm()">
      ...
</form>