In html if data unavailable use blank (or similar)

[skyewright]

Using v2.1

Experimenting with html templates I've found that if a particular value doesn't exist[1] at the moment when the page is requested the full variable name gets shown, which throws out formatting.

Might it be better if when the variable is valid but cannot be resolved to data it is replaced with either blank, or a dash (which is what the console would show) or N/A or some such, instead of the full variable name?

[1] e.g. [last60m_thb0_press_hpa], which at this moment isn't there because the sensor hasn't been picked up for over an hour.

[mvpel]

On a similar note, it'd be nice if a reference to a non-existent graph would show a message to that effect rather than a blank page.

(2.0d with Firefox 2.0.12)