The if_author tag is a conditional tag and always used as an opening and closing pair, like this…
<txp:if_author> ...conditional statement... </txp:if_author>
The tag will execute the contained statement if the called page is the result of an article search by a specific author’s name.
This is not the same as checking if the current article was written (posted) by the given author. Use if_article_author for that situation
Select a stylesheet based on author
Selects a stylesheet named “author_list” when a list by author “admin” is being displayed, or a stylesheet determined by the active section for normal page display.
<txp:if_author name="admin"> <link rel="stylesheet" href="<txp:css n="author_list" />" type="text/css" /> <txp:else /> <link rel="stylesheet" href="<txp:css />" type="text/css" /> </txp:if_author>