How to check checkbox in gridview in asp.net using jquery

<asp:GridView runat="server" CssClass="dataGridId" ID="gvCategorySms" DataKeyNames="MemberId"
                AutoGenerateColumns="false" CellPadding="3">
                <AlternatingRowStyle CssClass="dataGridItemId" />
                <HeaderStyle Wrap="False" HorizontalAlign="Left" CssClass="dataGridHeaderId" />
                <FooterStyle HorizontalAlign="Justify" CssClass="dataGridFooterId" />
                <RowStyle CssClass="dataGridAlternatingItemId" />
                <Columns>
                    <asp:TemplateField HeaderText="S.No">
                        <ItemTemplate>
                            <%#Container.DataItemIndex+1 %>
                        </ItemTemplate>
                    </asp:TemplateField>
                    <asp:TemplateField HeaderText="Student Name">
                        <ItemStyle Wrap="false" />
                        <ItemTemplate>
                            <asp:HiddenField Value='<%#Eval("MemberId")%>' runat="server" ID="hfMemberId" />
                            <asp:Label runat="server" ID="lblFullName" Text='<%#Eval("FullName") %>'></asp:Label>
                        </ItemTemplate>
                    </asp:TemplateField>
                    <asp:TemplateField HeaderText="Class Name">
                        <ItemStyle Wrap="false" />
                        <ItemTemplate>
                            <asp:Label runat="server" ID="lblFullClassName" Text='<%#Eval("FullClassName") %>'></asp:Label>
                        </ItemTemplate>
                    </asp:TemplateField>
                    <asp:TemplateField HeaderText="Roll Number">
                        <ItemStyle Wrap="false" />
                        <ItemTemplate>
                            <asp:Label runat="server" ID="lblRollNumber" Text='<%#Eval("RollNumber") %>'></asp:Label>
                        </ItemTemplate>
                    </asp:TemplateField>
                    <asp:TemplateField HeaderText="Mobile Number">
                        <ItemStyle Wrap="false" />
                        <ItemTemplate>
                            <asp:Label runat="server" ID="lblMobileNumber" Text='<%#Eval("MobileNumber") %>'></asp:Label>
                        </ItemTemplate>
                    </asp:TemplateField>
                    <asp:TemplateField ItemStyle-HorizontalAlign="Center">
                        <HeaderTemplate>
                            Select All
                            <input id="chkSelAll" type="checkbox" runat="server" /></HeaderTemplate>
                        <ItemTemplate>
                            <asp:CheckBox ID="chkSel" runat="server" />
                        </ItemTemplate>
                    </asp:TemplateField>
                </Columns>
                <AlternatingRowStyle BackColor="#E8E8E8 " ForeColor="#333333" />
            </asp:GridView>



<script type="text/javascript" src="../../Resources/JQuery/jquery-1.4.1.min.js"></script>


<script language="javascript" type="text/javascript">
         $(document).ready(function() {
           
            
             //gridview checkbox
            var chkBox = $("input[id$='gvCategorySms_ctl01_chkSelAll']");
            chkBox.click(function() {
                $("#gvCategorySms INPUT[type='checkbox']").attr('checked', chkBox.is(':checked'));
            });

            // To deselect CheckAll when a GridView CheckBox is unchecked
            $("#gvCategorySms INPUT[type='checkbox']").click(function(e) {
                if (!$(this)[0].checked) {
                    chkBox.attr("checked", false);
                   
                }
            });
                      
           
             $("#btnSubmit").click(function() {
             // Check for text box is Blank or not
             if ($("#txtDetails").val()=="")
             {
                 alert('Please enter sms content');
                 return false;
             }
            
             var countCheckBox=0
              $("#gvCategorySms INPUT[type='checkbox']").each(function(){
               if ($(this)[0].checked)
                 {
                    countCheckBox=1;
                 }
                
              });
             
               if(countCheckBox==0)
               {
                  alert("Please check at least one or more record(s)");
                return false;
                }
             });
           

           
                var textMaxLength = 200;
       // Start checking sms content
            $("#txtDetails").keyup(function(e) {
            $("#lblDetailsMax").text("[" + (textMaxLength-($(this).val().length)) + " characters left]");
                if ($(this).val().length > textMaxLength) {
                     alert('SMS Content '+ textMaxLength + " characters")
                    $(this).focus();
                    return false;
                    }
                });
        });
</script>