Question

How can we write client side validation for a text box.
for example:
If we have a login page then how to write the validation function to check the required field.

I have designed an application using master page. in this i am not getting script in the source page when i tried to write the code. I am getting error that only content controls are allowed means what. how to proceed i don’t understood.

Design of login page :

<div id="contenttext" align="center" >

        <tr>
            <td colspan="2" style="background-color: #E2E2E2">
                <asp:Label cssClass="orangelogotext"  runat="server" ID="lblinformation" Text="Login :"></asp:Label>
            </td>
        </tr>
        <tr>
            <td align="center" style="background-color: #E2E2E2">
                <asp:Label cssClass="smalltext"  runat="server" ID="lblEmail" Text="Email">
                </asp:Label>
            </td>
            <td style="background-color: #E2E2E2">
                <asp:TextBox runat="server" ID="Email" CssClass="textbox">
                </asp:TextBox>
            </td>
        </tr>
        <tr>
            <td align="center" style="background-color: #E2E2E2">
                <asp:Label cssClass="smalltext"  runat="server" ID="lblpassword" Text="Password" >
                </asp:Label>
            </td>
            <td style="background-color: #E2E2E2">
                <asp:TextBox runat="server" ID="Password"  Width="133px" TextMode="Password" CssClass="textbox"></asp:TextBox>
            </td>
        </tr>
        <tr>
            <td align="center" style="background-color: #E2E2E2">
                <asp:Label cssClass="smalltext"  runat="server" ID="lblorganisationname" Text="Organisation Name">
                </asp:Label>
            </td>
            <td style="background-color: #E2E2E2"> 
                <asp:DropDownList ID="ddlorganisationname" runat="server" DataTextField="OrganisationName"
                    DataValueField="OrganisationID" CssClass="textbox">
                </asp:DropDownList>
            </td>
        </tr>

        <tr>
            <td align="center" colspan="2" style="background-color: #E2E2E2">
                <asp:Button runat="server" ID="btnlogin" Text="LOGIN" Height="34px" onclick="btnlogin_Click;return validateForm()" CssClass="btntext" />
            </td>
        </tr>
    </table>

regards,
Dhriti

Answer 1

If you use a masterpage, ensure that all the content are inside <asp:Content> tags. Thats why you are getting only content controls are allowed error.

<asp:Content ID="Content1" ContentPlaceHolderID="Contentplaceholder1" runat="Server">
***all the content***
</asp:Content>