validate the textbox inside a repeator control

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C#

ASP.NET

jQuery

Hey,

I use a repeator control.
Inside that a textbox is placed, then I put a jQuery for validate that textbox.

When more than one textbox is generated inside the repeator control, this jQuery is not working (jQuery validator is working for the first textbox...).

When more than one textbox is generated the validation is not working.

Here is my jQuery.
Please refer that.

<script type="text/javascript">
         var retValue = false;

         function ValidateBlock() {
             var txtBlockName = $("input[attr-identity=txtBlockName]").val();

           //  txtBlockName = replaceSpace(txtBlockName);

             if (txtBlockName == "") {

                alert("Please Enter Block Name");
                 $("input[attr-identity=txtBlockName ]").val('');
                 $("input[attr-identity=txtBlockName ]").focus();

                 return false;
             }
             else {

                 return true;
             }
         }
</script>

In text box...
--------------

<asp:Repeater ID="RepBlockEntry" runat="server" OnItemDataBound="RepBlockEntry_ItemDataBound">
                                                   <ItemTemplate>

<asp:TextBox ID="txtBlockName" MaxLength="15" runat="server" Text='<%#Eval("BlockName") %>'
                                                                  OnTextChanged="txtBlockName_TextChanged" AutoPostBack="false" attr-identity="txtBlockName"></asp:TextBox>

</ItemTemplate>
    <FooterTemplate>
    </FooterTemplate>
</asp:Repeater>

On button ...
---------------------

<asp:Button ID="btnSaveBlock" runat="server" Text="Save" Visible="false" CssClass="addbutton" ValidationGroup="BlockEntry" OnClick="btnSubmitBlock_Click" OnClientClick="return ValidateBlock();" />