如何使用javascript获取gridview中的元素值

Question

我有一个gridview视图，其标签为lblPrice，文本框为txtQuanty，另外还有一个标签lblAmount。

<asp:GridView ID="gridItem2" HeaderStyle-BackColor="#FC8D10" HeaderStyle-ForeColor="White"
        RowStyle-BackColor="skyblue" AlternatingRowStyle-BackColor="White" AlternatingRowStyle-ForeColor="#000"
        runat="server" AutoGenerateColumns="False" AllowPaging="false" OnPageIndexChanging="gridItems_PageIndexChanging">
    <AlternatingRowStyle BackColor="White" ForeColor="#000000" />
    <Columns>
        <asp:TemplateField>
            <HeaderStyle Width="80px" HorizontalAlign="Center" />
            <HeaderTemplate>
                <p>Action</p>
            </HeaderTemplate>
            <ItemTemplate>
                <asp:ImageButton runat="server" CommandName="cmdDel" CommandArgument='<%#((GridViewRow)Container).RowIndex %>' Height="20" Width="20" />
            </ItemTemplate>
            <ItemStyle Width="80px" HorizontalAlign="Center" />
        </asp:TemplateField>
        <asp:TemplateField Visible="false">
            <HeaderTemplate>
                <asp:Label runat="server" Text="txt"></asp:Label>
            </HeaderTemplate>
            <ItemTemplate>
                <asp:Label runat="server" ID="lblItemId" Text='<%#Eval("itemId") %>'></asp:Label>
            </ItemTemplate>
        </asp:TemplateField>

        <asp:TemplateField Visible="true">
            <HeaderStyle Width="100px" />
            <HeaderTemplate>
                <asp:Label runat="server" Text="Items"></asp:Label>
            </HeaderTemplate>
            <ItemTemplate>
                <asp:Label runat="server" ID="lblName" Text='<%#Eval("name") %>'></asp:Label>
            </ItemTemplate>
        </asp:TemplateField>

        <asp:TemplateField Visible="true">
            <HeaderStyle Width="120px" />
            <HeaderTemplate>
                <asp:Label runat="server" Text="Price"></asp:Label>
            </HeaderTemplate>
            <ItemTemplate>
                <asp:Label runat="server" CssClass="clsPrice" ID="lblPrice" Text='<%#Eval("price") %>'></asp:Label>
            </ItemTemplate>
        </asp:TemplateField>

        <asp:TemplateField Visible="true">
            <HeaderStyle Width="120px" />
            <HeaderTemplate>
                <asp:Label runat="server" Text="Quantity"></asp:Label>
            </HeaderTemplate>
            <ItemTemplate>
                <asp:TextBox runat="server" onkeyup="myfunctionname(this.value);" CssClass="clsQuant" ID="txtQuant"></asp:TextBox>
            </ItemTemplate>
        </asp:TemplateField>

        <asp:TemplateField Visible="true">
            <HeaderStyle Width="120px" />
            <HeaderTemplate>
                <asp:Label runat="server" Text="Total"></asp:Label>
            </HeaderTemplate>
            <ItemTemplate>
                <asp:Label runat="server" ID="lblTotal"></asp:Label>
            </ItemTemplate>
        </asp:TemplateField>

    </Columns>
    <HeaderStyle BackColor="#3AC0F2" ForeColor="White" />
    <RowStyle BackColor="#A1DCF2" />
</asp:GridView>

我想在txtAmount上触发onkeyup事件，所以我使用这个jquery

function myfunctionname(amount) {
    var myvalue = "";
    myvalue=$('#gridItem2 input[type=text]').closest("tr").find(".clsPrice").text();
    alert(myvalue);
}

获取标签值但它获得所有标签的值。它不起作用。请提出建议