Set RadTextbox as Invalid programatically on client side

[Roberto Yudice]

Is there anyway to set a radtextbox as invalid so that it shows the warning icon using javascript?

[Dimo]

Hello Roberto,

Here is how to do it.

In order to remove the invalid state, you should set _invalid = false and call updateCssClass() again. This can be done in the RadTextBox' ValueChanged client handler or anywhere else.

<telerik:RadTextBox ID="RadTextBox1" runat="server" Text="RadTextBox" />

<asp:Button ID="Button1" runat="server" OnClientClick="return invalidate();" Text="click me" />

<script type="text/javascript">

function invalidate()
{
    var tb = $find("<%= RadTextBox1.ClientID %>");
    tb._invalid = true;
    tb.updateCssClass();

    return false;
}

</script>

Sincerely yours,
Dimo
the Telerik team