Code Sandbox Current Notes
{{If empty}} Returns an empty string.
{{If empty|one}} one one Returns the first parameter that is defined and not empty.
{{If empty|one|two}} one one
{{If empty|one|two|three|four}} one one
{{If empty||two}} two two The first parameter is empty/undefined, so is passed over.
{{If empty||two|three|four}} two two
{{If empty||two||four}} two two
{{If empty|||||||||nine}} nine nine
{{If empty||||||||||ten}} ten ten Empty string returned if maximum of nine parameters exceeded.
{{If empty|}} The only parameter is empty or undefined, so returns an empty string.
{{If empty||||}} Returns an empty string.
{{If empty|{{{1|}}}|{{{2|}}}|three}} three three
{{If empty|{{{1}}}|{{{2}}}|three}} {{{1}}} {{{1}}} No pipe-characters following the names of the first two parameters ("1" and "2"), so the first of these returned as text ("{{{1}}}").
{{If empty|{{{logo|}}}|two}} two two
{{If empty|{{{logo}}}|two}} {{{logo}}} {{{logo}}} No pipe-character following the parameter name "logo", so the text "{{{logo}}}" returned.
{{If empty|2=x}} Unnamed parameters must be defined sequentially.
{{If empty|p=q}} The template identifies the parameters it receives as parameters 1 to 9, not using names such as "p", etc.
{{If empty|one|{{X1}}[[Category:X1]]}} one one Parameters after the first non-empty parameter are not expanded, so this page does not transclude Template:X1 and is not in Category:X1.