I use NumericUpDownExtender but after execute function javascript , the textbox lose property readonly., and i have change value textbox manualy and it`s is bad. the function javascript: function EnabledTextBox() { if (document.getElementById("hddPanel").value == "Imagen") { var txtPrioridad = document.getElementById("txtPrioridad"); if (txtPrioridad != null) txtPrioridad.disabled = false; } else { var txtPrioridad2 = document.getElementById("txtPrioridad2"); if (txtPrioridad2 != null) txtPrioridad2.disabled = false; } } Mi: ajaxToolkit:NumericUpDownExtender <asp:TextBox ID="txtPrioridad" runat="server" CssClass="classPrioridadDisabled" Width="50px" onkeypress="return isNumberKey(event)"></asp:TextBox> <ajaxToolkit:NumericUpDownExtender ID="NumericUpDownExtender2" runat="ser ...

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