JavaScript

<asp:TemplateField HeaderText="End Time">
    <ItemTemplate>
        <asp:DropDownList id="endHour" runat="server">
            ...
        </asp:DropDownList>
        <asp:RequiredFieldValidator ID="RequiredFieldValidator5" runat="server"
            ControlToValidate="endHour"
            ErrorMessage="*"
            SetFocusOnError="True"
        />
        <asp:CustomValidator ID="CustomValidator1" runat="server"
            ControlToValidate="endHour"
            ErrorMessage="A minimum of four hours is required."
            Text="*"
            SetFocusOnError="True"
            OnServerValidate="ValidateDuration"
            ClientValidationFunction="validateDuration"
        />
    </ItemTemplate>
</asp:TemplateField>

protected void ValidateDuration(object sender, ServerValidateEventArgs args)
{
    Control validator = (Control)sender;
    Control row = validator.NamingContainer;
    
    int startHour = int.Parse(((DropDownList)row.FindControl("startHour")).SelectedValue);
    int startMinutes = int.Parse(((DropDownList)row.FindControl("startMinutes")).SelectedValue);
    string startAmPm = ((DropDownList)row.FindControl("startAmPm")).SelectedValue;
    
    switch (startAmPm)
    {
        case "AM":
        {
            if (startHour == 12)
            {
                startHour = 0;
            }
            break;
        }
        case "PM":
        {
            if (startHour != 12)
            {
                startHour += 12;
            }
            break;
        }
        default:
        {
            args.IsValid = true;
            return;
        }
    }
    
    int endHour = int.Parse(((DropDownList)row.FindControl("endHour")).SelectedValue);
    int endMinutes = int.Parse(((DropDownList)row.FindControl("endMinutes")).SelectedValue);
    string endAmPm = ((DropDownList)row.FindControl("endAmPm")).SelectedValue;
    
    switch (endAmPm)
    {
        case "AM":
        {
            if (endHour == 12)
            {
                endHour = 0;
            }
            break;
        }
        case "PM":
        {
            if (endHour != 12)
            {
                endHour += 12;
            }
            break;
        }
        default:
        {
            args.IsValid = true;
            return;
        }
    }
    
    int hourDiff = endHour - startHour;
    if (endMinutes < startMinutes)
    {
        hourDiff--;
    }
    
    args.IsValid = hourDiff >= 4;
} 

function validateDuration(sender, args){

    var row = $(sender).closest("tr");
    
    var startHour = parseInt(row.find("select[name$=startHour]").val(), 10);
    var startMinutes = parseInt(row.find("select[name$=startMinutes]").val(), 10);
    var startAmPm = row.find("select[name$=startAmPm]").val();
    
    switch (startAmPm) {
        case "AM": {
            if (startHour === 12) {
                startHour = 0;
            }
            break;
        }
        case "PM": {
            if (startHour !== 12) {
                startHour += 12;
            }
            break;
        }
        default: {
            args.IsValid = true;
            return;
        }
    }
    
    var endHour = parseInt(row.find("select[name$=endHour]").val(), 10);
    var endMinutes = parseInt(row.find("select[name$=endMinutes]").val(), 10);
    var endAmPm = row.find("select[name$=endAmPm]").val();
    
    switch (endAmPm) {
        case "AM": {
            if (endHour === 12) {
                endHour = 0;
            }
            break;
        }
        case "PM": {
            if (endHour !== 12) {
                endHour += 12;
            }
            break;
        }
        default: {
            args.IsValid = true;
            return;
        }
    }
    
    int hourDiff = endHour - startHour;
    if (endMinutes < startMinutes) { 
        hourDiff--; 
    }
    
    args.IsValid = hourDiff >= 4;
}

  var theDate =  $("table[id*=Gridview1] input[id*=txtdate]").val();
  var timeStart = new Date(theDate + ' ' + sHour + ':' + sMinutes + ' ' + sAmPm).getHours();
var timeEnd = new Date(theDate + ' ' + eHour + ':' + eMinutes + ' ' + eAmPm).getHours();

$('#btnSave').on('click', function () {

• Missing "f" from hourDiff within the if (endMinutes < startMinutes) block;
• Missing break statements from the switch clauses;
• jQuery selectors should be select[name$=...] instead of select[id$=...] due to changes in ASP.NET 4.0 ID generation;

Protected Sub ValidateDuration(ByVal sender As Object, ByVal args As ServerValidateEventArgs)
    Dim validator As Control = DirectCast(sender, Control)
    Dim row As Control = validator.NamingContainer

    Dim startHour As Integer = Integer.Parse(DirectCast(row.FindControl("startHour"), DropDownList).SelectedValue)
    Dim startMinutes As Integer = Integer.Parse(DirectCast(row.FindControl("startMinutes"), DropDownList).SelectedValue)
    Dim startAmPm As String = DirectCast(row.FindControl("startAmPm"), DropDownList).SelectedValue

    Select Case startAmPm
        Case "AM"
            If startHour = 12 Then
                startHour = 0
            End If
            
        Case "PM"
            If startHour <> 12 Then
                startHour += 12
            End If
            
        Case Else
            args.IsValid = True
            Return
    End Select

    Dim endHour As Integer = Integer.Parse(DirectCast(row.FindControl("endHour"), DropDownList).SelectedValue)
    Dim endMinutes As Integer = Integer.Parse(DirectCast(row.FindControl("endMinutes"), DropDownList).SelectedValue)
    Dim endAmPm As String = DirectCast(row.FindControl("endAmPm"), DropDownList).SelectedValue

    Select Case endAmPm
        Case "AM"
            If endHour = 12 Then
                endHour = 0
            End If
            
        Case "PM"
            If endHour <> 12 Then
                endHour += 12
            End If
            
        Case Else
            args.IsValid = True
            Return
    End Select

    Dim hourDiff As Integer = endHour - startHour
    If endMinutes < startMinutes Then
        hourDiff -= 1
    End If

    args.IsValid = hourDiff >= 4
End Sub

Protected Sub btnSave_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnSave.Click
    If Page.IsValid Then
        ' Update the database...
    End If
End Sub

var value = data[0]['Temperature']['Metric']['Value'];

var value = data[0].Temperature.Metric.Value;

ThetaClear wrote:

"I can't see what the logic behind detach/attach the event handler every time"

Quote:

You can see that you miss mouseOut when you move mouse too fast...So the thread can't keep up with you and drops events...