As a follow up to the previous TXP Tip on Article lists with alternate backgrounds, here is a method of styling every third article in a list differently from the others.

1. Download, install and activate the smd_if plugin – minimum version 0.8 required
2. Download, install and activate the adi_calc plugin

Your code

<txp:variable name="count" value="0" />
<txp:article wraptag="ul" sort="Posted asc">
	<txp:adi_calc name="count" add="1" />
	<txp:smd_if field="txpvar:count" operator="divisible" value="3">
		<txp:variable name="class" value="red" />
	<txp:else />
		<txp:variable name="class" value="normal" />
	</txp:smd_if>
	<li class="<txp:variable name="class"/>"><txp:title /></li>
</txp:article>

The article list is wrapped in a <ul> by the <txp:article/> tag and the individual articles are wrapped in a <li> within the form.

I set a counter to zero (a TXP variable called count) and increment it by one for each article in the list.

The counter is tested by smd_if to see if it is divisible by 3, and if it is then set a different class (i.e. red).

The normal or red class is applied to the <li>.

The result is that the 3rd, 6th, 9th … article title appears with a different (i.e. red) style.