inplace_textbox
Render a JS-aided inplace textbox.
Example:
{% inplace_textbox value="def.val." delegate="my_resource" hint="edit" %}
Clicking the displayed value replaces it with a text input. Leaving the input,
or pressing Enter, sends a postback to delegate. Use tag to set the
postback message and no_data_text for the label shown when the value is empty.
The class_input, class_label, class_hint, and class_no_data arguments
customize the generated elements.