Editing Template:Infobox/doc (section)

===Making fields optional===
A row with a label but no data is not displayed. This allows for the easy creation of optional infobox content rows. To make a row optional use a parameter that defaults to an empty string, like so:

<pre>
|label5 = Population
|data5  = {{{population|}}}
</pre>

This way if an article doesn't define the population parameter in its infobox the row won't be displayed.

For more complex fields with pre-formated contents that would still be present even if the parameter wasn't set, you can wrap it all in an "#if" statement to make the whole thing vanish when the parameter is not used. For instance, the "#if" statement in the following example reads "#if:the parameter ''mass'' has been supplied |then display it, followed by 'kg'":

<pre>
|label6 = Mass
|data6  = {{#if:{{{mass|}}}|{{{mass}}} kg}}
</pre>

For more on #if, see [[meta:ParserFunctions##if:|here]].

You can also make headers optional in a similar way. If you want a header to appear only if one or more of the data fields that fall under it are filled, one could use the following pattern as an example of how to do it:

<pre style="overflow:auto;">{{Infobox
|name    = {{subst:PAGENAME}}
|title   = Example of an optional header
|header1 = {{#if:{{{item_one|}}}{{{item_two|}}}{{{item_three|}}}|Optional header}}
|label2  = Item one
|data2   = {{{item_one|}}}
|label3  = Item two
|data3   = {{{item_two|}}}
|label4  = Item three
|data4   = {{{item_three|}}}
}}</pre>

header1 will be shown if any of item_one, item_two, or item_three is defined. If none of the three parameters are defined the header won't be shown.

The trick to this is that the "if" returns false only if there is nothing whatsoever in the conditional section, so only if all three of item_one, item_two and item_three are undefined will the if statement fail.