Editing Template:Infobox/doc (section)

=== Main data ===
; header(n) : Text to use as a header in row n.
; label(n) : Text to use as a label in row n.
; data(n) : Text to display as data in row n.

Note: for any given value for (n), not all combinations of parameters are permitted. The presence of a {{para|header''(n)''}} will cause the corresponding {{para|data''(n)''}} (and {{para|rowclass''(n)''}} {{para|label''(n)''}}, see below) to be ignored; the absence of a {{para|data''(n)''}} will cause the corresponding {{para|label''(n)''}} to be ignored. Valid combinations for any single row are:

* {{para|class''(n)''}} {{para|header''(n)''}}
* {{para|rowclass''(n)''}} {{para|class''(n)''}} {{para|data''(n)''}}
* {{para|rowclass''(n)''}} {{para|label''(n)''}} {{para|class''(n)''}} {{para|data''(n)''}}

See the rendering of header4, label4, and data4 in the [[#Examples|Examples]] section below.

==== Number ranges ====
To allow flexibility when the layout of an infobox is changed, it may be helpful when developing an infobox to use non-contiguous numbers for header and label/data rows. Parameters for new rows can then be inserted in future without having to renumber existing parameters. For example:

<pre style="overflow:auto">
 | header3  = Section 1
 |  label5  = Label A
 |   data5  = Data A
 |  label7  = Label C
 |   data7  = Data C
 | header10 = Section 2
 |  label12 = Label D
 |   data12 = Data D
</pre>{{clear}}

It is also possible to automatically renumber parameter names by using [[User:Frietjes/infoboxgap.js]] or [[Module:IncrementParams]].

==== Making data 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 style="overflow:auto">
 |  label5 = Population
 |   data5 = {{{population|}}}
</pre>{{clear}}

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-formatted 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 style="overflow:auto">
 |  label6 = Mass
 |   data6 = {{ #if: {{{mass|}}} | {{{mass}}} kg }}
</pre>{{clear}}

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

==== Hiding headers when all data fields are hidden ====
You can also make headers optional in a similar way. Consider this example:
{{Infobox
 | title   = Example of an undesirable header
 | header1 = Undesirable header
 |  label2 = Item 1      |   data2 =
 |  label3 = Item 2      |   data3 =
 |  label4 = Item 3      |   data4 =
 | header5 = Static header
 |  label6 = Static item |   data6 = Static value
}}
<pre style="overflow:auto">
{{Infobox
 | title   = Example of an undesirable header
 | header1 = Undesirable header
 |  label2 = Item 1      |   data2 =
 |  label3 = Item 2      |   data3 =
 |  label4 = Item 3      |   data4 =
 | header5 = Static header
 |  label6 = Static item |   data6 = Static value
}}
</pre>{{clear}}

If you want the first 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:

{{Infobox
 | title   = Example of an optional header
 | header1 = {{ #if: {{{item1|}}}{{{item2|}}}{{{item3|}}} | Optional header }}
 |  label2 = Item 1      |   data2 = {{{item1|}}}
 |  label3 = Item 2      |   data3 = {{{item2|}}}
 |  label4 = Item 3      |   data4 = {{{item3|}}}
 | header5 = Static header
 |  label6 = Static item |   data6 = Static value
}}
<pre style="overflow:auto">
{{Infobox
 | title   = Example of an optional header
 | header1 = {{ #if: {{{item1|}}}{{{item2|}}}{{{item3|}}} | Optional header }}
 |  label2 = Item 1      |   data2 = {{{item1|}}}
 |  label3 = Item 2      |   data3 = {{{item2|}}}
 |  label4 = Item 3      |   data4 = {{{item3|}}}
 | header5 = Static header
 |  label6 = Static item |   data6 = Static value
}}
</pre>{{clear}}

header1 will be shown if any of item1, item2, or item3 is defined. If none of the three parameters are defined the header won't be shown and no emty row appears before the next static content. 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 item1, item2 and item3 are undefined will the if statement fail.

Note that such trick may be sometimes very complex to test if there are many data items whose value depends on complex tests (or when a data row is generated by a recursive invokation of this template as a [[#Subboxes|subbox]]). Ideally, the Lua module supporting this template should now support a new way to make each header row autohideable by detecting if there is at least one non-empty data row after that header row (a parameter like "autohide header1 = yes", for example, would remove the need to perform the "#if" test so that we can just to define "header1 = Optional header"),