<com:TContent ID="Content">

<com:TActiveTextBox ID="ATB"  AutoPostBack="True" onTextChanged="onATB" /><br />
<com:TActiveCheckBox ID="ACB" AutoPostBack="True" /><br />
<com:TTextBox ID="TB"/><br />
Callbacks: <com:TActiveLabel ID="X" Text="0"/>

</com:TContent>