<extend src="layout.jael"> <block name="content"> <i if=message != null> <script> window.alert({{- json_message }}); </script> You said: {{ message }} </i> <form action="/" method="post"> <input name="message" placeholder="Say something..." type="text" value=message> <br> <input type="submit" value="Submit"> </form> </block> </extend>